SERVER-34730 Delete NetworkInterfaceASIO

48 files changed, 549 insertions, 6808 deletions

diff --git a/src/mongo/executor/SConscript b/src/mongo/executor/SConscript
index 6a6e061bf12..2f44dd45198 100644
--- a/src/mongo/executor/SConscript
+++ b/src/mongo/executor/SConscript
@@ -4,8 +4,6 @@ Import("env")
 
 env = env.Clone()
 
-env.InjectThirdPartyIncludePaths('asio')
-
 env.Library(
     target='connection_pool_stats',
     source=[
@@ -16,6 +14,13 @@ env.Library(
         '$BUILD_DIR/mongo/util/net/network',
     ])
 
+env.Library(target='async_timer_mock',
+            source=['async_timer_mock.cpp'],
+            LIBDEPS=[
+                '$BUILD_DIR/mongo/base',
+                '$BUILD_DIR/mongo/base/system_error',
+            ])
+
 env.Library(target='remote_command',
             source=[
                 'remote_command_request.cpp',
@@ -46,26 +51,6 @@ env.Library(target='task_executor_interface',
                 'remote_command',
             ])
 
-env.Library(target='async_timer_mock',
-            source=['async_timer_mock.cpp'],
-            LIBDEPS=[
-                '$BUILD_DIR/mongo/base',
-                '$BUILD_DIR/third_party/shim_asio',
-            ])
-
-env.CppUnitTest(target='async_timer_mock_test',
-                source=['async_timer_mock_test.cpp'],
-                LIBDEPS=[
-                    'async_timer_mock',
-                ])
-
-env.Library(target='async_timer_asio',
-            source=['async_timer_asio.cpp'],
-            LIBDEPS=[
-                '$BUILD_DIR/mongo/base',
-                '$BUILD_DIR/third_party/shim_asio',
-            ])
-
 env.Library(target='network_interface',
             source=['network_interface.cpp',],
             LIBDEPS=[
@@ -115,21 +100,6 @@ env.CppUnitTest(
     ],
 )
 
-env.CppIntegrationTest(
-    target='connection_pool_asio_integration_test',
-    source=[
-        'connection_pool_asio_integration_test.cpp',
-    ],
-    LIBDEPS=[
-        '$BUILD_DIR/mongo/rpc/command_status',
-        'network_interface_asio',
-        '$BUILD_DIR/mongo/executor/thread_pool_task_executor',
-        '$BUILD_DIR/mongo/executor/network_interface_thread_pool',
-        '$BUILD_DIR/mongo/executor/network_interface_factory',
-        '$BUILD_DIR/mongo/util/version_impl',
-    ],
-)
-
 env.CppUnitTest(
     target='network_interface_mock_test',
     source=[
@@ -169,6 +139,7 @@ env.Library(
     ],
     LIBDEPS_PRIVATE=[
         '$BUILD_DIR/mongo/db/auth/authcommon',
+        '$BUILD_DIR/mongo/db/commands/test_commands_enabled',
         '$BUILD_DIR/mongo/transport/transport_layer_manager',
         'connection_pool_executor',
         'network_interface',
@@ -176,87 +147,11 @@ env.Library(
 )
 
 env.Library(
-    target='network_interface_asio',
-    source=[
-        'connection_pool_asio.cpp',
-        'network_interface_asio.cpp',
-        'network_interface_asio_auth.cpp',
-        'network_interface_asio_command.cpp',
-        'network_interface_asio_connect.cpp',
-        'network_interface_asio_operation.cpp',
-    ],
-    LIBDEPS=[
-        '$BUILD_DIR/mongo/base',
-        '$BUILD_DIR/mongo/base/system_error',
-        '$BUILD_DIR/mongo/client/client_query',
-        '$BUILD_DIR/mongo/db/auth/authcommon',
-        '$BUILD_DIR/mongo/db/wire_version',
-        '$BUILD_DIR/mongo/rpc/command_status',
-        '$BUILD_DIR/mongo/rpc/rpc',
-        '$BUILD_DIR/mongo/transport/message_compressor',
-        '$BUILD_DIR/third_party/shim_asio',
-        'async_stream',
-        'async_timer_asio',
-        'connection_pool_executor',
-        'egress_tag_closer_manager',
-        'network_interface',
-        'task_executor_interface',
-    ],
-    LIBDEPS_PRIVATE=[
-        '$BUILD_DIR/mongo/db/commands/test_commands_enabled',
-    ],
-)
-
-env.Library(
-    target='async_stream',
+    target='network_interface_fixture',
     source=[
-        'async_secure_stream.cpp',
-        'async_secure_stream_factory.cpp',
-        'async_stream.cpp',
-        'async_stream_common.cpp',
-        'async_stream_factory.cpp',
+        'network_interface_integration_fixture.cpp'
     ],
     LIBDEPS=[
-        '$BUILD_DIR/mongo/base/system_error',
-        '$BUILD_DIR/mongo/client/authentication',
-        '$BUILD_DIR/mongo/util/net/ssl_manager',
-        '$BUILD_DIR/third_party/shim_asio',
-        'task_executor_interface',
-    ]
-)
-
-env.CppUnitTest(
-    target='async_stream_test',
-    source=[
-        'async_stream_test.cpp',
-    ],
-    LIBDEPS=[
-        'async_stream',
-    ]
-)
-
-env.CppUnitTest(
-    target='network_interface_asio_test',
-    source=[
-        'async_mock_stream_factory.cpp',
-        'network_interface_asio_test.cpp',
-    ],
-    LIBDEPS=[
-        'async_timer_mock',
-        'network_interface_asio',
-        '$BUILD_DIR/mongo/executor/thread_pool_task_executor',
-        '$BUILD_DIR/mongo/executor/network_interface_thread_pool',
-        '$BUILD_DIR/mongo/executor/network_interface_factory',
-        '$BUILD_DIR/mongo/util/version_impl',
-    ],
-)
-env.Library(
-    target='network_interface_asio_fixture',
-    source=[
-        'network_interface_asio_integration_fixture.cpp'
-    ],
-    LIBDEPS=[
-        'network_interface_asio',
         '$BUILD_DIR/mongo/unittest/integration_test_main',
         '$BUILD_DIR/mongo/executor/thread_pool_task_executor',
         '$BUILD_DIR/mongo/executor/network_interface_thread_pool',
@@ -268,33 +163,17 @@ env.Library(
 )
 
 env.CppIntegrationTest(
-    target='network_interface_asio_integration_test',
+    target='network_interface_integration_test',
     source=[
-        'network_interface_asio_integration_test.cpp',
+        'network_interface_integration_test.cpp',
     ],
     LIBDEPS=[
-        'network_interface_asio_fixture',
-    ],
-)
-
-env.CppIntegrationTest(
-    target='network_interface_perf_test',
-    source=[
-        'network_interface_perf_test.cpp',
-    ],
-    LIBDEPS=[
-        'network_interface_asio',
-        '$BUILD_DIR/mongo/executor/thread_pool_task_executor',
-        '$BUILD_DIR/mongo/executor/network_interface_thread_pool',
-        '$BUILD_DIR/mongo/executor/network_interface_factory',
-        '$BUILD_DIR/mongo/db/auth/authmocks',
-        '$BUILD_DIR/mongo/db/service_context_noop_init',
-        '$BUILD_DIR/mongo/rpc/command_status',
-        '$BUILD_DIR/mongo/util/version_impl',
+        'network_interface_fixture',
+        '$BUILD_DIR/mongo/db/commands/test_commands_enabled',
+        '$BUILD_DIR/mongo/db/wire_version',
     ],
 )
 
-
 env.Library(
     target='network_interface_factory',
     source=[
@@ -302,10 +181,10 @@ env.Library(
     ],
     LIBDEPS=[
         'network_interface',
-        'network_interface_asio',
-        'network_interface_tl',
+        'connection_pool_executor',
     ],
     LIBDEPS_PRIVATE=[
+        'network_interface_tl',
         'egress_tag_closer_manager',
     ])
 
@@ -345,23 +224,6 @@ env.Library(
     ]
 )
 
-env.CppUnitTest(
-    target='network_interface_thread_pool_test',
-    source=[
-        'network_interface_thread_pool_test.cpp',
-    ],
-    LIBDEPS=[
-        '$BUILD_DIR/mongo/util/concurrency/thread_pool_test_fixture',
-        'async_timer_mock',
-        'connection_pool_executor',
-        'network_interface_asio',
-        'network_interface_thread_pool',
-        '$BUILD_DIR/mongo/executor/thread_pool_task_executor',
-        '$BUILD_DIR/mongo/executor/network_interface_thread_pool',
-        '$BUILD_DIR/mongo/executor/network_interface_factory'
-    ],
-)
-
 env.Library(
     target='thread_pool_task_executor_test_fixture',
     source=[
diff --git a/src/mongo/executor/async_mock_stream_factory.cpp b/src/mongo/executor/async_mock_stream_factory.cpp
deleted file mode 100644
index 0d57e80ac5b..00000000000
--- a/src/mongo/executor/async_mock_stream_factory.cpp
+++ /dev/null
@@ -1,335 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/async_mock_stream_factory.h"
-
-#include <exception>
-#include <iterator>
-#include <system_error>
-
-#include "mongo/base/system_error.h"
-#include "mongo/rpc/command_reply_builder.h"
-#include "mongo/rpc/factory.h"
-#include "mongo/rpc/legacy_reply_builder.h"
-#include "mongo/rpc/message.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/util/assert_util.h"
-#include "mongo/util/log.h"
-
-namespace mongo {
-namespace executor {
-
-namespace {
-StringData stateToString(AsyncMockStreamFactory::MockStream::StreamState state) {
-    switch (state) {
-        case AsyncMockStreamFactory::MockStream::StreamState::kRunning:
-            return "Running";
-        case AsyncMockStreamFactory::MockStream::StreamState::kBlockedBeforeConnect:
-            return "Blocked before connect";
-        case AsyncMockStreamFactory::MockStream::StreamState::kBlockedAfterWrite:
-            return "Blocked after write";
-        case AsyncMockStreamFactory::MockStream::StreamState::kBlockedBeforeRead:
-            return "Blocked before read";
-        case AsyncMockStreamFactory::MockStream::StreamState::kCanceled:
-            return "Canceled";
-    }
-    MONGO_UNREACHABLE;
-}
-
-template <typename Handler>
-void checkCanceled(asio::io_service::strand* strand,
-                   AsyncMockStreamFactory::MockStream::StreamState* state,
-                   Handler&& handler,
-                   std::size_t bytes,
-                   std::error_code ec = std::error_code()) {
-    auto wasCancelled = (*state == AsyncMockStreamFactory::MockStream::StreamState::kCanceled);
-    *state = AsyncMockStreamFactory::MockStream::StreamState::kRunning;
-    strand->post([handler, wasCancelled, bytes, ec] {
-        handler(wasCancelled ? make_error_code(asio::error::operation_aborted) : ec, bytes);
-    });
-}
-
-}  // namespace
-
-std::unique_ptr<AsyncStreamInterface> AsyncMockStreamFactory::makeStream(
-    asio::io_service::strand* strand, const HostAndPort& target) {
-    return stdx::make_unique<MockStream>(strand, this, target);
-}
-
-void AsyncMockStreamFactory::_createStream(const HostAndPort& host, MockStream* stream) {
-    stdx::lock_guard<stdx::mutex> lk(_factoryMutex);
-    log() << "creating stream for: " << host;
-    _streams.emplace(host, stream);
-    _factoryCv.notify_all();
-}
-
-void AsyncMockStreamFactory::_destroyStream(const HostAndPort& host) {
-    stdx::lock_guard<stdx::mutex> lk(_factoryMutex);
-    log() << "destroying stream for: " << host;
-    _streams.erase(host);
-}
-
-AsyncMockStreamFactory::MockStream* AsyncMockStreamFactory::blockUntilStreamExists(
-    const HostAndPort& host) {
-    stdx::unique_lock<stdx::mutex> lk(_factoryMutex);
-
-    auto iter = std::begin(_streams);
-
-    _factoryCv.wait(lk, [&] { return (iter = _streams.find(host)) != std::end(_streams); });
-
-    return iter->second;
-}
-
-AsyncMockStreamFactory::MockStream::MockStream(asio::io_service::strand* strand,
-                                               AsyncMockStreamFactory* factory,
-                                               const HostAndPort& target)
-    : _strand(strand), _factory(factory), _target(target) {
-    _factory->_createStream(_target, this);
-}
-
-AsyncMockStreamFactory::MockStream::~MockStream() {
-    _factory->_destroyStream(_target);
-}
-
-void AsyncMockStreamFactory::MockStream::connect(asio::ip::tcp::resolver::iterator endpoints,
-                                                 ConnectHandler&& connectHandler) {
-    // Suspend execution after "connecting"
-    _defer(kBlockedBeforeConnect, [this, connectHandler, endpoints]() {
-        stdx::unique_lock<stdx::mutex> lk(_mutex);
-
-        // We shim a lambda to give connectHandler the right signature since it doesn't take
-        // a size_t param.
-        checkCanceled(
-            _strand,
-            &_state,
-            [connectHandler](std::error_code ec, std::size_t) { return connectHandler(ec); },
-            0);
-    });
-}
-
-void AsyncMockStreamFactory::MockStream::write(asio::const_buffer buf,
-                                               StreamHandler&& writeHandler) {
-    stdx::unique_lock<stdx::mutex> lk(_mutex);
-
-    auto begin = asio::buffer_cast<const uint8_t*>(buf);
-    auto size = asio::buffer_size(buf);
-    _writeQueue.push({begin, begin + size});
-
-    // Suspend execution after data is written.
-    _defer_inlock(kBlockedAfterWrite, [this, writeHandler, size]() {
-        stdx::unique_lock<stdx::mutex> lk(_mutex);
-        checkCanceled(_strand, &_state, std::move(writeHandler), size);
-    });
-}
-
-void AsyncMockStreamFactory::MockStream::cancel() {
-    stdx::unique_lock<stdx::mutex> lk(_mutex);
-    log() << "cancel() for: " << _target;
-
-    // If _state is kRunning then we don't have a deferred operation to cancel.
-    if (_state == kRunning) {
-        return;
-    }
-
-    _state = kCanceled;
-}
-
-void AsyncMockStreamFactory::MockStream::read(asio::mutable_buffer buf,
-                                              StreamHandler&& readHandler) {
-    // Suspend execution before data is read.
-    _defer(kBlockedBeforeRead, [this, buf, readHandler]() {
-        stdx::unique_lock<stdx::mutex> lk(_mutex);
-        int nToCopy = 0;
-
-        // If we've set an error, return that instead of a read.
-        if (!_error) {
-            auto nextRead = std::move(_readQueue.front());
-            _readQueue.pop();
-
-            auto beginDst = asio::buffer_cast<uint8_t*>(buf);
-            nToCopy = std::min(nextRead.size(), asio::buffer_size(buf));
-
-            auto endSrc = std::begin(nextRead);
-            std::advance(endSrc, nToCopy);
-
-            auto endDst = std::copy(std::begin(nextRead), endSrc, beginDst);
-            invariant((endDst - beginDst) == static_cast<std::ptrdiff_t>(nToCopy));
-            log() << "read " << nToCopy << " bytes, " << (nextRead.size() - nToCopy)
-                  << " remaining in buffer";
-        }
-
-        auto handler = readHandler;
-
-        // If we did not receive all the bytes, we should return an error
-        if (static_cast<size_t>(nToCopy) < asio::buffer_size(buf)) {
-            handler = [readHandler](std::error_code ec, size_t len) {
-                // If we have an error here we've been canceled, and that takes precedence
-                if (ec)
-                    return readHandler(ec, len);
-
-                // Call the original handler with an error
-                readHandler(make_error_code(ErrorCodes::InvalidLength), len);
-            };
-        }
-
-        checkCanceled(_strand, &_state, std::move(handler), nToCopy, _error);
-        _error.clear();
-    });
-}
-
-void AsyncMockStreamFactory::MockStream::pushRead(std::vector<uint8_t> toRead) {
-    stdx::unique_lock<stdx::mutex> lk(_mutex);
-    invariant(_state != kRunning);
-    _readQueue.emplace(std::move(toRead));
-}
-
-void AsyncMockStreamFactory::MockStream::setError(std::error_code ec) {
-    _error = ec;
-}
-
-std::vector<uint8_t> AsyncMockStreamFactory::MockStream::popWrite() {
-    stdx::unique_lock<stdx::mutex> lk(_mutex);
-    invariant(_state != kRunning);
-    auto nextWrite = std::move(_writeQueue.front());
-    _writeQueue.pop();
-    return nextWrite;
-}
-
-void AsyncMockStreamFactory::MockStream::_defer(StreamState state, Action&& handler) {
-    stdx::unique_lock<stdx::mutex> lk(_mutex);
-    _defer_inlock(state, std::move(handler));
-}
-
-void AsyncMockStreamFactory::MockStream::_defer_inlock(StreamState state, Action&& handler) {
-    invariant(_state == kRunning);
-    _state = state;
-
-    invariant(!_deferredAction);
-    _deferredAction = std::move(handler);
-    _deferredCV.notify_one();
-}
-
-void AsyncMockStreamFactory::MockStream::unblock() {
-    stdx::unique_lock<stdx::mutex> lk(_mutex);
-    _unblock_inlock();
-}
-
-void AsyncMockStreamFactory::MockStream::_unblock_inlock() {
-    // Can be canceled here at which point we will call the handler with the CallbackCanceled
-    // status when we invoke the _deferredAction.
-    invariant(_state != kRunning);
-
-    if (_state != kCanceled) {
-        _state = kRunning;
-    }
-    // Post our deferred action to resume state machine execution
-    invariant(_deferredAction);
-    _strand->post(std::move(_deferredAction));
-    _deferredAction = nullptr;
-}
-
-auto AsyncMockStreamFactory::MockStream::waitUntilBlocked() -> StreamState {
-    stdx::unique_lock<stdx::mutex> lk(_mutex);
-    _deferredCV.wait(lk, [this]() { return _state != kRunning; });
-    log() << "returning from waitUntilBlocked, state: " << stateToString(_state);
-    return _state;
-}
-
-HostAndPort AsyncMockStreamFactory::MockStream::target() {
-    return _target;
-}
-
-void AsyncMockStreamFactory::MockStream::simulateServer(
-    rpc::Protocol proto,
-    const stdx::function<RemoteCommandResponse(RemoteCommandRequest)> replyFunc) {
-    std::exception_ptr ex;
-    uint32_t messageId = 0;
-
-    RemoteCommandResponse resp;
-    {
-        WriteEvent write{this};
-
-        std::vector<uint8_t> messageData = popWrite();
-        Message msg(SharedBuffer::allocate(messageData.size()));
-        memcpy(msg.buf(), messageData.data(), messageData.size());
-
-        auto request = rpc::opMsgRequestFromAnyProtocol(msg);
-        ASSERT(rpc::protocolForMessage(msg) == proto);
-
-        RemoteCommandRequest rcr(target(), request.getDatabase().toString(), request.body, nullptr);
-
-        messageId = msg.header().getId();
-
-        // So we can allow ASSERTs in replyFunc, we capture any exceptions, but rethrow
-        // them later to prevent deadlock
-        try {
-            resp = replyFunc(std::move(rcr));
-        } catch (...) {
-            ex = std::current_exception();
-        }
-    }
-
-    auto replyBuilder = rpc::makeReplyBuilder(proto);
-    replyBuilder->setCommandReply(resp.data);
-    replyBuilder->setMetadata(resp.metadata);
-
-    auto replyMsg = replyBuilder->done();
-    replyMsg.header().setResponseToMsgId(messageId);
-
-    {
-        // The first read will be for the header.
-        ReadEvent read{this};
-        auto hdrBytes = reinterpret_cast<const uint8_t*>(replyMsg.header().view2ptr());
-        pushRead({hdrBytes, hdrBytes + sizeof(MSGHEADER::Value)});
-    }
-
-    {
-        // The second read will be for the message data.
-        ReadEvent read{this};
-        auto dataBytes = reinterpret_cast<const uint8_t*>(replyMsg.buf());
-        auto pastHeader = dataBytes;
-        std::advance(pastHeader, sizeof(MSGHEADER::Value));
-        pushRead({pastHeader, dataBytes + static_cast<std::size_t>(replyMsg.size())});
-    }
-
-    if (ex) {
-        // Rethrow ASSERTS after the NIA completes it's Write-Read-Read sequence.
-        std::rethrow_exception(ex);
-    }
-}
-
-bool AsyncMockStreamFactory::MockStream::isOpen() {
-    return true;
-}
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/async_mock_stream_factory.h b/src/mongo/executor/async_mock_stream_factory.h
deleted file mode 100644
index 6f65edd8425..00000000000
--- a/src/mongo/executor/async_mock_stream_factory.h
+++ /dev/null
@@ -1,226 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include <asio.hpp>
-#include <cstdint>
-#include <memory>
-#include <queue>
-
-#include "mongo/executor/async_stream_factory_interface.h"
-#include "mongo/executor/async_stream_interface.h"
-#include "mongo/executor/remote_command_request.h"
-#include "mongo/executor/remote_command_response.h"
-#include "mongo/rpc/protocol.h"
-#include "mongo/stdx/condition_variable.h"
-#include "mongo/stdx/functional.h"
-#include "mongo/stdx/mutex.h"
-#include "mongo/stdx/unordered_map.h"
-#include "mongo/unittest/unittest.h"
-#include "mongo/util/net/hostandport.h"
-
-namespace mongo {
-namespace executor {
-
-class AsyncStreamInterface;
-
-/**
- * A factory that produces mock streams to allow for testing of NetworkInterfaceASIO.
- *
- * The streams produced by this factory simulate a flow of Events (ConnectEvent,
- * ReadEvent, WriteEvent). The streams created by this factory will automatically
- * pause themselves at each Event, and the caller must unblock them by destroying
- * the Event object to continue.
- *
- * Example use of this factory:
- *
- *     AsyncMockStreamFactory factory();
- *
- *     // NIA will then call makeStream(...) to create new streams from the
- *     // factory, or the caller can do this manually.
- *
- *     // Wait for the desired stream to exist
- *     auto stream = streamFactory.blockUntilStreamExists(host);
- *
- *     // If we do not care to inspect after a certain event, we can skip it:
- *     ConnectEvent{stream}.skip();
- *
- *     // To examine the stream at an Event, instantiate the event object.
- *     // When the Event object goes out of scope the stream will unblock.
- *     {
- *         WriteEvent write{stream};
- *
- *         // Inspect what NIA wrote to this stream:
- *         auto messageData = stream->popWrite();
- *         ...
- *     }
- *
- *     // The Event object will keep the stream blocked as long as it exists.
- *     // Use this window to perform operations on the stream or inspect it.
- *     {
- *         ReadEvent read{stream};
- *
- *         // Simulate data sent to this stream over the network
- *         stream->pushRead( ... );
- *
- *         // Or, simulate a networking error
- *         stream->setError( error_code );
- *     }
- */
-class AsyncMockStreamFactory final : public AsyncStreamFactoryInterface {
-public:
-    AsyncMockStreamFactory() = default;
-
-    std::unique_ptr<AsyncStreamInterface> makeStream(asio::io_service::strand* strand,
-                                                     const HostAndPort& host) override;
-
-    /**
-     * A mock stream class for testing the egress networking layer.
-     *
-     * At the core of this class is an idea of deferring actions and allowing inspection
-     * of state of the stream before those actions happen.
-     *
-     * This class operates on the assumption that two threads are in use: a networking
-     * thread used by NIA to issue IO calls on the MockStream, and a test thread to
-     * wait on those calls and react.
-     *
-     * When the test thread creates an Event object, the constructor sends it to wait
-     * on a condition variable. When NIA issues an IO call on the stream, the MockStream
-     * load the proper handler into a placeholder, and then calls notify() on the
-     * condition variable. At that point the stream is paused and the test thread
-     * may operate on it.
-     */
-    class MockStream final : public AsyncStreamInterface {
-    public:
-        MockStream(asio::io_service::strand* strand,
-                   AsyncMockStreamFactory* factory,
-                   const HostAndPort& target);
-
-        // Use unscoped enum so we can specialize on it
-        enum StreamState {
-            kRunning,
-            kBlockedBeforeConnect,
-            kBlockedBeforeRead,
-            kBlockedAfterWrite,
-            kCanceled,
-        };
-
-        ~MockStream();
-
-        void connect(asio::ip::tcp::resolver::iterator endpoints,
-                     ConnectHandler&& connectHandler) override;
-        void write(asio::const_buffer buf, StreamHandler&& writeHandler) override;
-        void read(asio::mutable_buffer buf, StreamHandler&& readHandler) override;
-
-        bool isOpen() override;
-
-        HostAndPort target();
-
-        StreamState waitUntilBlocked();
-
-        void cancel() override;
-
-        std::vector<uint8_t> popWrite();
-        void pushRead(std::vector<uint8_t> toRead);
-
-        void setError(std::error_code ec);
-
-        void unblock();
-
-        void simulateServer(
-            rpc::Protocol proto,
-            const stdx::function<RemoteCommandResponse(RemoteCommandRequest)> replyFunc);
-
-    private:
-        using Action = stdx::function<void()>;
-
-        void _defer(StreamState state, Action&& handler);
-        void _defer_inlock(StreamState state, Action&& handler);
-        void _unblock_inlock();
-
-        asio::io_service::strand* _strand;
-
-        AsyncMockStreamFactory* _factory;
-        HostAndPort _target;
-
-        stdx::mutex _mutex;
-
-        stdx::condition_variable _deferredCV;
-        StreamState _state{kRunning};
-
-        std::queue<std::vector<uint8_t>> _readQueue;
-        std::queue<std::vector<uint8_t>> _writeQueue;
-
-        std::error_code _error;
-
-        Action _deferredAction;
-    };
-
-    MockStream* blockUntilStreamExists(const HostAndPort& host);
-
-private:
-    void _createStream(const HostAndPort& host, MockStream* stream);
-    void _destroyStream(const HostAndPort& host);
-
-    stdx::mutex _factoryMutex;
-    stdx::condition_variable _factoryCv;
-
-    stdx::unordered_map<HostAndPort, MockStream*> _streams;
-};
-
-template <int EventType>
-class StreamEvent {
-public:
-    StreamEvent(AsyncMockStreamFactory::MockStream* stream) : _stream(stream) {
-        ASSERT(stream->waitUntilBlocked() == EventType);
-    }
-
-    void skip() {
-        _stream->unblock();
-        skipped = true;
-    }
-
-    ~StreamEvent() {
-        if (!skipped) {
-            skip();
-        }
-    }
-
-private:
-    bool skipped = false;
-    AsyncMockStreamFactory::MockStream* _stream = nullptr;
-};
-
-using ReadEvent = StreamEvent<AsyncMockStreamFactory::MockStream::StreamState::kBlockedBeforeRead>;
-using WriteEvent = StreamEvent<AsyncMockStreamFactory::MockStream::StreamState::kBlockedAfterWrite>;
-using ConnectEvent =
-    StreamEvent<AsyncMockStreamFactory::MockStream::StreamState::kBlockedBeforeConnect>;
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/async_secure_stream.cpp b/src/mongo/executor/async_secure_stream.cpp
deleted file mode 100644
index eb69bd5d18e..00000000000
--- a/src/mongo/executor/async_secure_stream.cpp
+++ /dev/null
@@ -1,125 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/async_secure_stream.h"
-
-#include "mongo/base/system_error.h"
-#include "mongo/config.h"
-#include "mongo/executor/async_stream_common.h"
-#include "mongo/util/log.h"
-#include "mongo/util/net/ssl_manager.h"
-
-#ifdef MONGO_CONFIG_SSL
-
-namespace mongo {
-namespace executor {
-
-AsyncSecureStream::AsyncSecureStream(asio::io_service::strand* strand,
-                                     asio::ssl::context* sslContext)
-    : _strand(strand), _stream(_strand->get_io_service(), *sslContext, "") {}
-
-AsyncSecureStream::~AsyncSecureStream() {
-    destroyStream(&_stream.lowest_layer(), _connected);
-}
-
-void AsyncSecureStream::connect(asio::ip::tcp::resolver::iterator endpoints,
-                                ConnectHandler&& connectHandler) {
-    // Stash the connectHandler as we won't be able to call it until we re-enter the state
-    // machine.
-    _userHandler = std::move(connectHandler);
-    asio::async_connect(
-        _stream.lowest_layer(),
-        std::move(endpoints),
-        _strand->wrap([this](std::error_code ec, asio::ip::tcp::resolver::iterator iter) {
-            if (ec) {
-                return _userHandler(ec);
-            }
-
-            ec = setStreamNonBlocking(&_stream.next_layer());
-            if (ec) {
-                return _userHandler(ec);
-            }
-
-            ec = setStreamNoDelay(&_stream.next_layer());
-            if (ec) {
-                return _userHandler(ec);
-            }
-
-            _connected = true;
-            return _handleConnect(std::move(iter));
-        }));
-}
-
-void AsyncSecureStream::write(asio::const_buffer buffer, StreamHandler&& streamHandler) {
-    writeStream(&_stream, _strand, _connected, buffer, std::move(streamHandler));
-}
-
-void AsyncSecureStream::read(asio::mutable_buffer buffer, StreamHandler&& streamHandler) {
-    readStream(&_stream, _strand, _connected, buffer, std::move(streamHandler));
-}
-
-void AsyncSecureStream::_handleConnect(asio::ip::tcp::resolver::iterator iter) {
-    _stream.async_handshake(decltype(_stream)::client,
-                            _strand->wrap([this, iter](std::error_code ec) {
-                                if (ec) {
-                                    return _userHandler(ec);
-                                }
-                                return _handleHandshake(ec, iter->host_name());
-                            }));
-}
-
-void AsyncSecureStream::_handleHandshake(std::error_code ec, const std::string& hostName) {
-    auto certStatus =
-        getSSLManager()->parseAndValidatePeerCertificate(_stream.native_handle(), hostName);
-    if (certStatus.isOK()) {
-        _userHandler(make_error_code(ErrorCodes::OK));
-    } else {
-        warning() << "Failed to validate peer certificate during SSL handshake: "
-                  << certStatus.getStatus();
-        // We aren't able to propagate error extra info through here so make sure we only use a code
-        // that won't have any.
-        _userHandler(make_error_code(ErrorCodes::SSLHandshakeFailed));
-    }
-}
-
-void AsyncSecureStream::cancel() {
-    cancelStream(&_stream.lowest_layer());
-}
-
-bool AsyncSecureStream::isOpen() {
-    return checkIfStreamIsOpen(&_stream.next_layer(), _connected);
-}
-
-}  // namespace executor
-}  // namespace mongo
-
-#endif
diff --git a/src/mongo/executor/async_secure_stream.h b/src/mongo/executor/async_secure_stream.h
deleted file mode 100644
index cead9d6fada..00000000000
--- a/src/mongo/executor/async_secure_stream.h
+++ /dev/null
@@ -1,74 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include "mongo/config.h"
-
-#ifdef MONGO_CONFIG_SSL
-
-#include <asio.hpp>
-
-#include "mongo/executor/async_stream_interface.h"
-#include "mongo/util/net/ssl.hpp"
-
-namespace mongo {
-namespace executor {
-
-class AsyncSecureStream final : public AsyncStreamInterface {
-public:
-    AsyncSecureStream(asio::io_service::strand* strand, asio::ssl::context* sslContext);
-
-    ~AsyncSecureStream();
-
-    void connect(asio::ip::tcp::resolver::iterator endpoints,
-                 ConnectHandler&& connectHandler) override;
-
-    void write(asio::const_buffer buffer, StreamHandler&& streamHandler) override;
-
-    void read(asio::mutable_buffer buffer, StreamHandler&& streamHandler) override;
-
-    void cancel() override;
-
-    bool isOpen() override;
-
-private:
-    void _handleConnect(asio::ip::tcp::resolver::iterator iter);
-
-    void _handleHandshake(std::error_code ec, const std::string& hostName);
-
-    asio::io_service::strand* const _strand;
-    asio::ssl::stream<asio::ip::tcp::socket> _stream;
-    ConnectHandler _userHandler;
-    bool _connected = false;
-};
-
-}  // namespace executor
-}  // namespace mongo
-
-#endif
diff --git a/src/mongo/executor/async_secure_stream_factory.cpp b/src/mongo/executor/async_secure_stream_factory.cpp
deleted file mode 100644
index a907dbe894d..00000000000
--- a/src/mongo/executor/async_secure_stream_factory.cpp
+++ /dev/null
@@ -1,69 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/async_secure_stream_factory.h"
-
-#include "mongo/config.h"
-#include "mongo/executor/async_secure_stream.h"
-#include "mongo/executor/async_stream.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/util/net/ssl_manager.h"
-#include "mongo/util/net/ssl_options.h"
-
-#ifdef MONGO_CONFIG_SSL
-
-namespace mongo {
-namespace executor {
-
-AsyncSecureStreamFactory::AsyncSecureStreamFactory(SSLManagerInterface* sslManager)
-    : _sslContext(asio::ssl::context::sslv23) {
-    // We use sslv23, which corresponds to OpenSSLs SSLv23_method, for compatibility with older
-    // versions of OpenSSL. This mirrors the call to SSL_CTX_new in ssl_manager.cpp. In
-    // initAsyncSSLContext we explicitly disable all protocols other than TLSv1, TLSv1.1,
-    // and TLSv1.2.
-    uassertStatusOK(
-        sslManager->initSSLContext(_sslContext.native_handle(),
-                                   getSSLGlobalParams(),
-                                   SSLManagerInterface::ConnectionDirection::kOutgoing));
-}
-
-std::unique_ptr<AsyncStreamInterface> AsyncSecureStreamFactory::makeStream(
-    asio::io_service::strand* strand, const HostAndPort&) {
-    int sslModeVal = getSSLGlobalParams().sslMode.load();
-    if (sslModeVal == SSLParams::SSLMode_preferSSL || sslModeVal == SSLParams::SSLMode_requireSSL) {
-        return stdx::make_unique<AsyncSecureStream>(strand, &_sslContext);
-    }
-    return stdx::make_unique<AsyncStream>(strand);
-}
-
-}  // namespace executor
-}  // namespace mongo
-
-#endif
diff --git a/src/mongo/executor/async_secure_stream_factory.h b/src/mongo/executor/async_secure_stream_factory.h
deleted file mode 100644
index ad25ad487d9..00000000000
--- a/src/mongo/executor/async_secure_stream_factory.h
+++ /dev/null
@@ -1,60 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include "mongo/config.h"
-
-#ifdef MONGO_CONFIG_SSL
-
-#include <asio.hpp>
-
-#include "mongo/executor/async_stream_factory_interface.h"
-#include "mongo/util/net/ssl.hpp"
-
-namespace mongo {
-class SSLManagerInterface;
-namespace executor {
-
-class AsyncStreamInterface;
-
-class AsyncSecureStreamFactory final : public AsyncStreamFactoryInterface {
-public:
-    AsyncSecureStreamFactory(SSLManagerInterface* sslManager);
-
-    std::unique_ptr<AsyncStreamInterface> makeStream(asio::io_service::strand* strand,
-                                                     const HostAndPort&) override;
-
-private:
-    asio::ssl::context _sslContext;
-};
-
-}  // namespace executor
-}  // namespace mongo
-
-#endif
diff --git a/src/mongo/executor/async_stream.cpp b/src/mongo/executor/async_stream.cpp
deleted file mode 100644
index 075a9094dd4..00000000000
--- a/src/mongo/executor/async_stream.cpp
+++ /dev/null
@@ -1,95 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/async_stream.h"
-#include "mongo/executor/async_stream_common.h"
-#include "mongo/util/assert_util.h"
-#include "mongo/util/log.h"
-
-namespace mongo {
-namespace executor {
-
-using asio::ip::tcp;
-
-AsyncStream::AsyncStream(asio::io_service::strand* strand)
-    : _strand(strand), _stream(_strand->get_io_service()) {}
-
-AsyncStream::~AsyncStream() {
-    destroyStream(&_stream, _connected);
-}
-
-void AsyncStream::connect(tcp::resolver::iterator iter, ConnectHandler&& connectHandler) {
-    asio::async_connect(
-        _stream,
-        std::move(iter),
-        // We need to wrap this with a lambda of the right signature so it compiles, even
-        // if we don't actually use the resolver iterator.
-        _strand->wrap([this, connectHandler](std::error_code ec, tcp::resolver::iterator iter) {
-            if (ec) {
-                return connectHandler(ec);
-            }
-
-            // We assume that our owner is responsible for keeping us alive until we call
-            // connectHandler, so _connected should always be a valid memory location.
-            ec = setStreamNonBlocking(&_stream);
-            if (ec) {
-                return connectHandler(ec);
-            }
-
-            ec = setStreamNoDelay(&_stream);
-            if (ec) {
-                return connectHandler(ec);
-            }
-
-            _connected = true;
-            return connectHandler(ec);
-        }));
-}
-
-void AsyncStream::write(asio::const_buffer buffer, StreamHandler&& streamHandler) {
-    writeStream(&_stream, _strand, _connected, buffer, std::move(streamHandler));
-}
-
-void AsyncStream::read(asio::mutable_buffer buffer, StreamHandler&& streamHandler) {
-    readStream(&_stream, _strand, _connected, buffer, std::move(streamHandler));
-}
-
-void AsyncStream::cancel() {
-    cancelStream(&_stream);
-}
-
-bool AsyncStream::isOpen() {
-    return checkIfStreamIsOpen(&_stream, _connected);
-}
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/async_stream.h b/src/mongo/executor/async_stream.h
deleted file mode 100644
index 3a9c9d42b15..00000000000
--- a/src/mongo/executor/async_stream.h
+++ /dev/null
@@ -1,61 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include <asio.hpp>
-
-#include "mongo/executor/async_stream_interface.h"
-
-namespace mongo {
-namespace executor {
-
-class AsyncStream final : public AsyncStreamInterface {
-public:
-    AsyncStream(asio::io_service::strand* strand);
-
-    ~AsyncStream();
-
-    void connect(asio::ip::tcp::resolver::iterator iter, ConnectHandler&& connectHandler) override;
-
-    void write(asio::const_buffer buffer, StreamHandler&& streamHandler) override;
-
-    void read(asio::mutable_buffer buffer, StreamHandler&& streamHandler) override;
-
-    void cancel() override;
-
-    bool isOpen() override;
-
-private:
-    asio::io_service::strand* const _strand;
-    asio::ip::tcp::socket _stream;
-    bool _connected = false;
-};
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/async_stream_common.cpp b/src/mongo/executor/async_stream_common.cpp
deleted file mode 100644
index 92708862c94..00000000000
--- a/src/mongo/executor/async_stream_common.cpp
+++ /dev/null
@@ -1,68 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/async_stream_common.h"
-
-#include "mongo/util/log.h"
-
-namespace mongo {
-namespace executor {
-
-void logCloseFailed(std::error_code ec) {
-    invariant(ec);
-    log() << "Failed to close stream: " << ec.message();
-}
-
-void logCancelFailed(std::error_code ec) {
-    invariant(ec);
-    log() << "Failed to cancel stream: " << ec.message();
-}
-
-void logFailureInSetStreamNonBlocking(std::error_code ec) {
-    invariant(ec);
-    severe() << "Failed to set non-blocking mode on stream: " << ec.message();
-}
-
-void logFailureInSetStreamNoDelay(std::error_code ec) {
-    invariant(ec);
-    severe() << "Failed to set no-delay mode on stream: " << ec.message();
-}
-
-void logUnexpectedErrorInCheckOpen(std::error_code ec) {
-    invariant(ec);
-    log() << "unexpected error when checking if a stream was open: " << ec.message()
-          << ", the only errors we expect are EOF and network/connection reset";
-}
-
-
-}  // namespace executor
-}  // namespace  mongo
diff --git a/src/mongo/executor/async_stream_common.h b/src/mongo/executor/async_stream_common.h
deleted file mode 100644
index 67c12bbff3b..00000000000
--- a/src/mongo/executor/async_stream_common.h
+++ /dev/null
@@ -1,146 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#include <asio.hpp>
-#include <system_error>
-#include <utility>
-
-#include "mongo/util/assert_util.h"
-
-namespace mongo {
-namespace executor {
-
-void logCloseFailed(std::error_code ec);
-
-template <typename ASIOStream>
-void destroyStream(ASIOStream* stream, bool connected) {
-    if (!connected) {
-        return;
-    }
-
-    std::error_code ec;
-
-    stream->shutdown(asio::ip::tcp::socket::shutdown_both, ec);
-    if (ec) {
-        logCloseFailed(ec);
-    }
-
-    stream->close(ec);
-    if (ec) {
-        logCloseFailed(ec);
-    }
-}
-
-template <typename ASIOStream, typename Buffer, typename Handler>
-void writeStream(ASIOStream* stream,
-                 asio::io_service::strand* strand,
-                 bool connected,
-                 Buffer&& buffer,
-                 Handler&& handler) {
-    invariant(connected);
-    asio::async_write(*stream,
-                      asio::buffer(std::forward<Buffer>(buffer)),
-                      strand->wrap(std::forward<Handler>(handler)));
-}
-
-template <typename ASIOStream, typename Buffer, typename Handler>
-void readStream(ASIOStream* stream,
-                asio::io_service::strand* strand,
-                bool connected,
-                Buffer&& buffer,
-                Handler&& handler) {
-    invariant(connected);
-    asio::async_read(*stream,
-                     asio::buffer(std::forward<Buffer>(buffer)),
-                     strand->wrap(std::forward<Handler>(handler)));
-}
-
-void logCancelFailed(std::error_code ec);
-
-template <typename ASIOStream>
-void cancelStream(ASIOStream* stream) {
-    std::error_code ec;
-    stream->cancel(ec);
-    if (ec) {
-        logCancelFailed(ec);
-    }
-}
-
-void logFailureInSetStreamNonBlocking(std::error_code ec);
-void logFailureInSetStreamNoDelay(std::error_code ec);
-
-template <typename ASIOStream>
-std::error_code setStreamNonBlocking(ASIOStream* stream) {
-    std::error_code ec;
-    stream->non_blocking(true, ec);
-    if (ec) {
-        logFailureInSetStreamNonBlocking(ec);
-    }
-    return ec;
-}
-
-template <typename ASIOStream>
-std::error_code setStreamNoDelay(ASIOStream* stream) {
-    std::error_code ec;
-    stream->set_option(asio::ip::tcp::no_delay(true), ec);
-    if (ec) {
-        logFailureInSetStreamNoDelay(ec);
-    }
-    return ec;
-}
-
-void logUnexpectedErrorInCheckOpen(std::error_code ec);
-
-template <typename ASIOStream>
-bool checkIfStreamIsOpen(ASIOStream* stream, bool connected) {
-    if (!connected) {
-        return false;
-    };
-    std::error_code ec;
-    std::array<char, 1> buf;
-    // Although we call the blocking form of receive, we ensure the socket is in non-blocking mode.
-    // ASIO implements receive on POSIX using the 'recvmsg' system call, which returns immediately
-    // if the socket is non-blocking and in a valid state, but there is no data to receive. On
-    // windows, receive is implemented with WSARecv, which has the same semantics.
-    invariant(stream->non_blocking());
-    stream->receive(asio::buffer(buf), asio::socket_base::message_peek, ec);
-    if (!ec || ec == asio::error::would_block || ec == asio::error::try_again) {
-        // If the read worked or we got EWOULDBLOCK or EAGAIN (since we are in non-blocking mode),
-        // we assume the socket is still open.
-        return true;
-    } else if (ec == asio::error::eof || ec == asio::error::connection_reset ||
-               ec == asio::error::network_reset) {
-        return false;
-    }
-    // We got a different error. Log it and return false so we throw the connection away.
-    logUnexpectedErrorInCheckOpen(ec);
-    return false;
-}
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/async_stream_factory.cpp b/src/mongo/executor/async_stream_factory.cpp
deleted file mode 100644
index 5f24adf341b..00000000000
--- a/src/mongo/executor/async_stream_factory.cpp
+++ /dev/null
@@ -1,47 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/async_stream_factory.h"
-
-#include "mongo/executor/async_secure_stream.h"
-#include "mongo/executor/async_stream.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/util/assert_util.h"
-
-namespace mongo {
-namespace executor {
-
-std::unique_ptr<AsyncStreamInterface> AsyncStreamFactory::makeStream(
-    asio::io_service::strand* strand, const HostAndPort&) {
-    return stdx::make_unique<AsyncStream>(strand);
-}
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/async_stream_factory.h b/src/mongo/executor/async_stream_factory.h
deleted file mode 100644
index bbf9767427b..00000000000
--- a/src/mongo/executor/async_stream_factory.h
+++ /dev/null
@@ -1,49 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include <memory>
-
-#include "mongo/executor/async_stream_factory_interface.h"
-
-namespace mongo {
-namespace executor {
-
-class AsyncStreamInterface;
-
-class AsyncStreamFactory final : public AsyncStreamFactoryInterface {
-public:
-    AsyncStreamFactory() = default;
-
-    std::unique_ptr<AsyncStreamInterface> makeStream(asio::io_service::strand* strand,
-                                                     const HostAndPort&) override;
-};
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/async_stream_factory_interface.h b/src/mongo/executor/async_stream_factory_interface.h
deleted file mode 100644
index c894a1fee5a..00000000000
--- a/src/mongo/executor/async_stream_factory_interface.h
+++ /dev/null
@@ -1,59 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include <asio.hpp>
-#include <memory>
-
-#include "mongo/base/disallow_copying.h"
-
-namespace mongo {
-struct HostAndPort;
-namespace executor {
-
-class AsyncStreamInterface;
-
-/**
- * A factory for AsyncStream creation to support mocking.
- */
-class AsyncStreamFactoryInterface {
-    MONGO_DISALLOW_COPYING(AsyncStreamFactoryInterface);
-
-public:
-    virtual ~AsyncStreamFactoryInterface() = default;
-
-    virtual std::unique_ptr<AsyncStreamInterface> makeStream(asio::io_service::strand* strand,
-                                                             const HostAndPort& target) = 0;
-
-protected:
-    AsyncStreamFactoryInterface() = default;
-};
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/async_stream_interface.h b/src/mongo/executor/async_stream_interface.h
deleted file mode 100644
index ca97e350923..00000000000
--- a/src/mongo/executor/async_stream_interface.h
+++ /dev/null
@@ -1,70 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include <asio.hpp>
-#include <memory>
-#include <system_error>
-
-#include "mongo/base/disallow_copying.h"
-#include "mongo/stdx/functional.h"
-
-namespace mongo {
-namespace executor {
-
-/**
- * A bidirectional stream supporting asynchronous reads and writes.
- */
-class AsyncStreamInterface {
-    MONGO_DISALLOW_COPYING(AsyncStreamInterface);
-
-public:
-    virtual ~AsyncStreamInterface() = default;
-
-    using ConnectHandler = stdx::function<void(std::error_code)>;
-
-    using StreamHandler = stdx::function<void(std::error_code, std::size_t)>;
-
-    virtual void connect(asio::ip::tcp::resolver::iterator endpoints,
-                         ConnectHandler&& connectHandler) = 0;
-
-    virtual void write(asio::const_buffer buf, StreamHandler&& writeHandler) = 0;
-
-    virtual void read(asio::mutable_buffer buf, StreamHandler&& readHandler) = 0;
-
-    virtual void cancel() = 0;
-
-    virtual bool isOpen() = 0;
-
-protected:
-    AsyncStreamInterface() = default;
-};
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/async_stream_test.cpp b/src/mongo/executor/async_stream_test.cpp
deleted file mode 100644
index 2731df5d713..00000000000
--- a/src/mongo/executor/async_stream_test.cpp
+++ /dev/null
@@ -1,144 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include <asio.hpp>
-#include <system_error>
-#include <vector>
-
-#include "mongo/executor/async_stream.h"
-#include "mongo/executor/network_interface_asio_test_utils.h"
-#include "mongo/platform/atomic_word.h"
-#include "mongo/stdx/mutex.h"
-#include "mongo/stdx/thread.h"
-#include "mongo/unittest/unittest.h"
-#include "mongo/util/assert_util.h"
-#include "mongo/util/log.h"
-#include "mongo/util/scopeguard.h"
-
-namespace mongo {
-namespace {
-
-using asio::ip::tcp;
-
-class Server {
-public:
-    void startup() {
-        _thread = stdx::thread([this] {
-            try {
-                tcp::acceptor acceptor{_io_service,
-                                       // Let the OS choose the accepting port.
-                                       tcp::endpoint{asio::ip::make_address_v4("127.0.0.1"), 0}};
-                _endpoint.emplace(acceptor.local_endpoint());
-                tcp::socket socket{_io_service};
-                _started.emplace(true);
-                acceptor.accept(socket);
-                log() << "got incoming connection";
-                _stopped.get();
-                log() << "shutting down socket";
-                socket.shutdown(tcp::socket::shutdown_both);
-            } catch (...) {
-                log() << exceptionToStatus();
-            }
-        });
-        _started.get();
-    }
-
-    // idempotent
-    void shutdown() {
-        _stopped.emplace(true);
-        _thread.join();
-    }
-
-    Server() {
-        startup();
-    }
-
-    tcp::endpoint endpoint() {
-        return _endpoint.get();
-    }
-
-    ~Server() {
-        if (!_stopped.hasCompleted()) {
-            shutdown();
-        }
-    }
-
-private:
-    stdx::thread _thread;
-    executor::Deferred<bool> _started;
-    executor::Deferred<bool> _stopped;
-    executor::Deferred<tcp::endpoint> _endpoint;
-    asio::io_service _io_service;
-    std::vector<tcp::socket> _sockets;
-};
-
-TEST(AsyncStreamTest, IsOpen) {
-    Server server;
-    asio::io_service io_service;
-    stdx::thread clientWorker([&io_service] {
-        log() << "starting clientWorker";
-        asio::io_service::work work(io_service);
-        io_service.run();
-    });
-    auto guard = MakeGuard([&clientWorker, &io_service] {
-        io_service.stop();
-        clientWorker.join();
-    });
-    asio::io_service::strand strand{io_service};
-    executor::AsyncStream stream{&strand};
-    ASSERT_FALSE(stream.isOpen());
-
-    tcp::resolver resolver{io_service};
-    auto endpoints = resolver.resolve(server.endpoint());
-
-    executor::Deferred<bool> opened;
-
-    log() << "opening up outgoing connection";
-    stream.connect(endpoints, [opened](std::error_code ec) mutable {
-        log() << "opened outgoing connection";
-        opened.emplace(!ec);
-    });
-
-    ASSERT_TRUE(opened.get());
-    ASSERT_TRUE(stream.isOpen());
-
-    server.shutdown();
-
-    // There is nothing we can wait on to determinstically know when
-    // the socket will transition to closed. Busy wait for that.
-    while (stream.isOpen()) {
-        stdx::this_thread::sleep_for(Milliseconds(1).toSystemDuration());
-    }
-}
-
-}  // namespace
-}  // namespace mongo
diff --git a/src/mongo/executor/async_timer_asio.cpp b/src/mongo/executor/async_timer_asio.cpp
deleted file mode 100644
index bc287540e93..00000000000
--- a/src/mongo/executor/async_timer_asio.cpp
+++ /dev/null
@@ -1,72 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/async_timer_asio.h"
-
-#include "mongo/stdx/chrono.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/util/log.h"
-
-namespace mongo {
-namespace executor {
-
-AsyncTimerASIO::AsyncTimerASIO(asio::io_service::strand* strand, Milliseconds expiration)
-    : _strand(strand), _timer(_strand->get_io_service(), expiration.toSystemDuration()) {}
-
-void AsyncTimerASIO::cancel() {
-    std::error_code ec;
-    _timer.cancel(ec);
-    if (ec) {
-        log() << "Failed to cancel timer: " << ec.message();
-    }
-}
-
-void AsyncTimerASIO::asyncWait(AsyncTimerInterface::Handler handler) {
-    _timer.async_wait(_strand->wrap(std::move(handler)));
-}
-
-void AsyncTimerASIO::expireAfter(Milliseconds expiration) {
-    _timer.expires_after(stdx::chrono::milliseconds(expiration.count()));
-}
-
-std::unique_ptr<AsyncTimerInterface> AsyncTimerFactoryASIO::make(asio::io_service::strand* strand,
-                                                                 Milliseconds expiration) {
-    return stdx::make_unique<AsyncTimerASIO>(strand, expiration);
-}
-
-Date_t AsyncTimerFactoryASIO::now() {
-    return Date_t::fromDurationSinceEpoch(asio::system_timer::clock_type::now() -
-                                          asio::system_timer::clock_type::from_time_t(0));
-}
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/async_timer_asio.h b/src/mongo/executor/async_timer_asio.h
deleted file mode 100644
index 01e1fbe18b8..00000000000
--- a/src/mongo/executor/async_timer_asio.h
+++ /dev/null
@@ -1,65 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include <asio.hpp>
-#include <asio/system_timer.hpp>
-
-#include "mongo/executor/async_timer_interface.h"
-
-namespace mongo {
-namespace executor {
-
-class AsyncTimerASIO final : public AsyncTimerInterface {
-public:
-    AsyncTimerASIO(asio::io_service::strand* strand, Milliseconds expiration);
-
-    void cancel() override;
-
-    void asyncWait(AsyncTimerInterface::Handler handler) override;
-
-    void expireAfter(Milliseconds expiration) override;
-
-private:
-    asio::io_service::strand* const _strand;
-    asio::system_timer _timer;
-};
-
-class AsyncTimerFactoryASIO final : public AsyncTimerFactoryInterface {
-public:
-    AsyncTimerFactoryASIO() = default;
-
-    std::unique_ptr<AsyncTimerInterface> make(asio::io_service::strand* strand,
-                                              Milliseconds expiration) override;
-
-    Date_t now() override;
-};
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/async_timer_interface.h b/src/mongo/executor/async_timer_interface.h
index fdfce5b39d8..3076a8f68b6 100644
--- a/src/mongo/executor/async_timer_interface.h
+++ b/src/mongo/executor/async_timer_interface.h
@@ -30,8 +30,6 @@
 
 #include <system_error>
 
-#include <asio.hpp>
-
 #include "mongo/base/disallow_copying.h"
 #include "mongo/stdx/functional.h"
 #include "mongo/util/time_support.h"
@@ -87,8 +85,7 @@ class AsyncTimerFactoryInterface {
 public:
     virtual ~AsyncTimerFactoryInterface() = default;
 
-    virtual std::unique_ptr<AsyncTimerInterface> make(asio::io_service::strand* strand,
-                                                      Milliseconds expiration) = 0;
+    virtual std::unique_ptr<AsyncTimerInterface> make(Milliseconds expiration) = 0;
 
     virtual Date_t now() = 0;
 
diff --git a/src/mongo/executor/async_timer_mock.cpp b/src/mongo/executor/async_timer_mock.cpp
index 39c9323612d..87904dd284b 100644
--- a/src/mongo/executor/async_timer_mock.cpp
+++ b/src/mongo/executor/async_timer_mock.cpp
@@ -28,6 +28,7 @@
 
 #include "mongo/executor/async_timer_mock.h"
 
+#include "mongo/base/system_error.h"
 #include "mongo/stdx/memory.h"
 
 namespace mongo {
@@ -40,7 +41,7 @@ const Milliseconds kZeroMilliseconds = Milliseconds(0);
 AsyncTimerMockImpl::AsyncTimerMockImpl(Milliseconds expiration) : _timeLeft(expiration) {}
 
 void AsyncTimerMockImpl::cancel() {
-    _callAllHandlers(asio::error::operation_aborted);
+    _callAllHandlers(std::error_code(ErrorCodes::CallbackCanceled, mongoErrorCategory()));
 }
 
 void AsyncTimerMockImpl::asyncWait(AsyncTimerInterface::Handler handler) {
@@ -95,7 +96,7 @@ void AsyncTimerMockImpl::expireAfter(Milliseconds expiration) {
 
     // Call handlers with a "canceled" error code
     for (const auto& handler : tmp) {
-        handler(asio::error::operation_aborted);
+        handler(std::error_code(ErrorCodes::CallbackCanceled, mongoErrorCategory()));
     }
 }
 
@@ -131,11 +132,6 @@ void AsyncTimerMock::expireAfter(Milliseconds expiration) {
 }
 
 std::unique_ptr<AsyncTimerInterface> AsyncTimerFactoryMock::make(Milliseconds expiration) {
-    return make(nullptr, expiration);
-}
-
-std::unique_ptr<AsyncTimerInterface> AsyncTimerFactoryMock::make(asio::io_service::strand* strand,
-                                                                 Milliseconds expiration) {
     stdx::lock_guard<stdx::recursive_mutex> lk(_timersMutex);
     auto elem = _timers.emplace(std::make_shared<AsyncTimerMockImpl>(expiration));
     return stdx::make_unique<AsyncTimerMock>(*elem.first);
diff --git a/src/mongo/executor/async_timer_mock.h b/src/mongo/executor/async_timer_mock.h
index ad77d323f5e..20f6c039f8e 100644
--- a/src/mongo/executor/async_timer_mock.h
+++ b/src/mongo/executor/async_timer_mock.h
@@ -124,13 +124,7 @@ public:
     /**
      * Create and return a new AsyncTimerMock object.
      */
-    std::unique_ptr<AsyncTimerInterface> make(Milliseconds expiration);
-
-    /**
-     * Create and return a new AsyncTimerMock object.
-     */
-    std::unique_ptr<AsyncTimerInterface> make(asio::io_service::strand* strand,
-                                              Milliseconds expiration) override;
+    std::unique_ptr<AsyncTimerInterface> make(Milliseconds expiration) override;
 
     /**
      * Advance the current "time" and make stale timers expire.
diff --git a/src/mongo/executor/async_timer_mock_test.cpp b/src/mongo/executor/async_timer_mock_test.cpp
deleted file mode 100644
index 53b0dbbb598..00000000000
--- a/src/mongo/executor/async_timer_mock_test.cpp
+++ /dev/null
@@ -1,170 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kNetwork
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/async_timer_mock.h"
-#include "mongo/stdx/future.h"
-#include "mongo/unittest/unittest.h"
-
-namespace mongo {
-namespace executor {
-
-TEST(AsyncTimerMock, BasicTest) {
-    AsyncTimerFactoryMock factory;
-
-    // Set an early timer
-    bool timer1Fired = false;
-    auto timer1 = factory.make(Milliseconds(1000));
-    timer1->asyncWait([&timer1Fired](std::error_code ec) {
-        ASSERT(!ec);
-        timer1Fired = true;
-    });
-
-    // Set a later timer
-    bool timer2Fired = false;
-    auto timer2 = factory.make(Milliseconds(2000));
-    timer2->asyncWait([&timer2Fired](std::error_code ec) {
-        ASSERT(!ec);
-        timer2Fired = true;
-    });
-
-    // Advance clock a little, nothing should fire
-    factory.fastForward(Milliseconds(500));
-    ASSERT(!timer1Fired);
-    ASSERT(!timer2Fired);
-
-    // Advance clock so early timer fires
-    factory.fastForward(Milliseconds(600));
-    ASSERT(timer1Fired);
-
-    // Second timer should still be waiting
-    ASSERT(!timer2Fired);
-
-    // Advance clock so second timer fires
-    factory.fastForward(Milliseconds(1000));
-    ASSERT(timer2Fired);
-}
-
-TEST(AsyncTimerMock, Cancel) {
-    AsyncTimerFactoryMock factory;
-
-    // Set a timer
-    bool fired = false;
-    auto timer = factory.make(Milliseconds(100));
-    timer->asyncWait([&fired](std::error_code ec) {
-        // This timer should have been canceled
-        ASSERT(ec);
-        ASSERT(ec == asio::error::operation_aborted);
-        fired = true;
-    });
-
-    // Cancel timer
-    timer->cancel();
-
-    // Ensure that its handler was called
-    ASSERT(fired);
-}
-
-TEST(AsyncTimerMock, CancelExpired) {
-    AsyncTimerFactoryMock factory;
-
-    // Set a timer
-    bool fired = false;
-    auto timer = factory.make(Milliseconds(100));
-    timer->asyncWait([&fired](std::error_code ec) {
-        // This timer should NOT have been canceled
-        ASSERT(!ec);
-        fired = true;
-    });
-
-    // Fast forward so it expires
-    factory.fastForward(Milliseconds(200));
-    ASSERT(fired);
-
-    fired = false;
-
-    // Cancel it, should not fire again
-    timer->cancel();
-    ASSERT(!fired);
-}
-
-TEST(AsyncTimerMock, Now) {
-    AsyncTimerFactoryMock factory;
-
-    ASSERT(factory.now() == Date_t::fromMillisSinceEpoch(0));
-
-    factory.fastForward(Milliseconds(200));
-    ASSERT(factory.now() == Date_t::fromMillisSinceEpoch(200));
-
-    factory.fastForward(Milliseconds(1000));
-    ASSERT(factory.now() == Date_t::fromMillisSinceEpoch(1200));
-
-    factory.fastForward(Milliseconds(1022));
-    ASSERT(factory.now() == Date_t::fromMillisSinceEpoch(2222));
-}
-
-TEST(AsyncTimerMock, WorksAfterCancel) {
-    AsyncTimerFactoryMock factory;
-
-    // Set a timer
-    bool fired1 = false;
-    auto timer = factory.make(Milliseconds(100));
-    timer->asyncWait([&fired1](std::error_code ec) {
-        // This timer should have been canceled
-        ASSERT(ec);
-        ASSERT(ec == asio::error::operation_aborted);
-        fired1 = true;
-    });
-
-    // Cancel timer
-    timer->cancel();
-
-    // Ensure that its handler was called
-    ASSERT(fired1);
-
-    fired1 = false;
-    bool fired2 = false;
-
-    // Add a new callback to to timer.
-    timer->asyncWait([&fired2](std::error_code ec) {
-        // This timer should NOT have been canceled
-        ASSERT(!ec);
-        fired2 = true;
-    });
-
-    // Fast forward so it expires
-    factory.fastForward(Milliseconds(100));
-    ASSERT(fired2);
-    ASSERT(!fired1);
-}
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/connection_pool_asio.cpp b/src/mongo/executor/connection_pool_asio.cpp
deleted file mode 100644
index 028316349db..00000000000
--- a/src/mongo/executor/connection_pool_asio.cpp
+++ /dev/null
@@ -1,333 +0,0 @@
-/** *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/connection_pool_asio.h"
-
-#include <asio.hpp>
-
-#include "mongo/executor/async_stream_factory_interface.h"
-#include "mongo/executor/network_interface_asio.h"
-#include "mongo/rpc/factory.h"
-#include "mongo/rpc/legacy_request_builder.h"
-#include "mongo/rpc/reply_interface.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/util/log.h"
-
-namespace mongo {
-namespace executor {
-namespace connection_pool_asio {
-
-ASIOTimer::ASIOTimer(asio::io_service::strand* strand)
-    : _strand(strand),
-      _impl(strand->get_io_service()),
-      _callbackSharedState(std::make_shared<CallbackSharedState>()) {}
-
-ASIOTimer::~ASIOTimer() {
-    stdx::lock_guard<stdx::mutex> lk(_callbackSharedState->mutex);
-    ++_callbackSharedState->id;
-}
-
-const auto kMaxTimerDuration = duration_cast<Milliseconds>(ASIOTimer::clock_type::duration::max());
-
-void ASIOTimer::setTimeout(Milliseconds timeout, TimeoutCallback cb) {
-    _strand->dispatch([this, timeout, cb] {
-        _cb = std::move(cb);
-
-        cancelTimeout();
-
-        try {
-            _impl.expires_after(std::min(kMaxTimerDuration, timeout).toSystemDuration());
-        } catch (const asio::system_error& ec) {
-            severe() << "Failed to set connection pool timer: " << ec.what();
-            fassertFailed(40333);
-        }
-
-        decltype(_callbackSharedState->id) id;
-        decltype(_callbackSharedState) sharedState;
-
-        {
-            stdx::lock_guard<stdx::mutex> lk(_callbackSharedState->mutex);
-            id = ++_callbackSharedState->id;
-            sharedState = _callbackSharedState;
-        }
-
-        _impl.async_wait(_strand->wrap([this, id, sharedState](const asio::error_code& error) {
-            if (error == asio::error::operation_aborted) {
-                return;
-            }
-
-            stdx::unique_lock<stdx::mutex> lk(sharedState->mutex);
-
-            // If the id in shared state doesn't match the id in our callback, it
-            // means we were cancelled, but still executed. This can occur if we
-            // were cancelled just before our timeout. We need a generation, rather
-            // than just a bool here, because we could have been cancelled and
-            // another callback set, in which case we shouldn't run and the we
-            // should let the other callback execute instead.
-            if (sharedState->id == id) {
-                auto cb = std::move(_cb);
-                lk.unlock();
-                cb();
-            }
-        }));
-    });
-}
-
-void ASIOTimer::cancelTimeout() {
-    decltype(_callbackSharedState) sharedState;
-    decltype(_callbackSharedState->id) id;
-    {
-        stdx::lock_guard<stdx::mutex> lk(_callbackSharedState->mutex);
-        id = ++_callbackSharedState->id;
-        sharedState = _callbackSharedState;
-    }
-    _strand->dispatch([this, id, sharedState] {
-        stdx::lock_guard<stdx::mutex> lk(sharedState->mutex);
-        if (sharedState->id != id)
-            return;
-
-        std::error_code ec;
-        _impl.cancel(ec);
-        if (ec) {
-            log() << "Failed to cancel connection pool timer: " << ec.message();
-        }
-    });
-}
-
-ASIOConnection::ASIOConnection(const HostAndPort& hostAndPort, size_t generation, ASIOImpl* global)
-    : _global(global),
-      _hostAndPort(hostAndPort),
-      _generation(generation),
-      _impl(makeAsyncOp(this)),
-      _timer(&_impl->strand()) {}
-
-ASIOConnection::~ASIOConnection() {
-    if (_impl) {
-        stdx::lock_guard<stdx::mutex> lk(_impl->_access->mutex);
-        _impl->_access->id++;
-    }
-}
-
-void ASIOConnection::indicateSuccess() {
-    _status = Status::OK();
-}
-
-void ASIOConnection::indicateFailure(Status status) {
-    invariant(!status.isOK());
-    _status = std::move(status);
-}
-
-const HostAndPort& ASIOConnection::getHostAndPort() const {
-    return _hostAndPort;
-}
-
-bool ASIOConnection::isHealthy() {
-    // Check if the remote host has closed the connection.
-    return _impl->connection().stream().isOpen();
-}
-
-void ASIOConnection::indicateUsed() {
-    // It is illegal to attempt to use a connection after calling indicateFailure().
-    invariant(_status.isOK() || _status == ConnectionPool::kConnectionStateUnknown);
-    _lastUsed = _global->now();
-}
-
-Date_t ASIOConnection::getLastUsed() const {
-    return _lastUsed;
-}
-
-const Status& ASIOConnection::getStatus() const {
-    return _status;
-}
-
-size_t ASIOConnection::getGeneration() const {
-    return _generation;
-}
-
-std::unique_ptr<NetworkInterfaceASIO::AsyncOp> ASIOConnection::makeAsyncOp(ASIOConnection* conn) {
-    return stdx::make_unique<NetworkInterfaceASIO::AsyncOp>(
-        conn->_global->_impl,
-        TaskExecutor::CallbackHandle(),
-        RemoteCommandRequest{conn->getHostAndPort(),
-                             std::string("admin"),
-                             BSON("isMaster" << 1),
-                             BSONObj(),
-                             nullptr},
-        [conn](const TaskExecutor::ResponseStatus& rs) {
-            auto cb = std::move(conn->_setupCallback);
-            cb(conn, rs.status);
-        },
-        conn->_global->now());
-}
-
-Message ASIOConnection::makeIsMasterRequest(ASIOConnection* conn) {
-    return rpc::legacyRequestFromOpMsgRequest(
-        OpMsgRequest::fromDBAndBody("admin", BSON("isMaster" << 1)));
-}
-
-void ASIOConnection::setTimeout(Milliseconds timeout, TimeoutCallback cb) {
-    _timer.setTimeout(timeout, std::move(cb));
-}
-
-void ASIOConnection::cancelTimeout() {
-    _timer.cancelTimeout();
-}
-
-void ASIOConnection::setup(Milliseconds timeout, SetupCallback cb) {
-    _impl->strand().dispatch([this, timeout, cb] {
-        _setupCallback = [this, cb](ConnectionInterface* ptr, Status status) {
-            {
-                stdx::lock_guard<stdx::mutex> lk(_impl->_access->mutex);
-                _impl->_access->id++;
-
-                // If our connection timeout callback ran but wasn't the reason we exited
-                // the state machine, clear any TIMED_OUT state.
-                if (status.isOK()) {
-                    _impl->_transitionToState_inlock(
-                        NetworkInterfaceASIO::AsyncOp::State::kUninitialized);
-                    _impl->_transitionToState_inlock(
-                        NetworkInterfaceASIO::AsyncOp::State::kInProgress);
-                    _impl->_transitionToState_inlock(
-                        NetworkInterfaceASIO::AsyncOp::State::kFinished);
-                }
-            }
-
-            cancelTimeout();
-            cb(ptr, status);
-        };
-
-        // Capturing the shared access pad and generation before calling setTimeout gives us enough
-        // information to avoid calling the timer if we shouldn't without needing any other
-        // resources that might have been cleaned up.
-        decltype(_impl->_access) access;
-        std::size_t generation;
-        {
-            stdx::lock_guard<stdx::mutex> lk(_impl->_access->mutex);
-            access = _impl->_access;
-            generation = access->id;
-        }
-
-        // Actually timeout setup
-        setTimeout(timeout, [this, access, generation] {
-            stdx::lock_guard<stdx::mutex> lk(access->mutex);
-            if (generation != access->id) {
-                // The operation has been cleaned up, do not access.
-                return;
-            }
-            _impl->timeOut_inlock();
-        });
-
-        _global->_impl->_connect(_impl.get());
-    });
-}
-
-void ASIOConnection::resetToUnknown() {
-    _status = ConnectionPool::kConnectionStateUnknown;
-}
-
-void ASIOConnection::refresh(Milliseconds timeout, RefreshCallback cb) {
-    _impl->strand().dispatch([this, timeout, cb] {
-        auto op = _impl.get();
-
-        // We clear state transitions because we're re-running a portion of the asio state machine
-        // without entering in startCommand (which would call this for us).
-        op->clearStateTransitions();
-
-        _refreshCallback = std::move(cb);
-
-        // Actually timeout refreshes
-        setTimeout(timeout, [this] { _impl->connection().stream().cancel(); });
-
-        // Our pings are isMaster's
-        auto beginStatus = op->beginCommand(makeIsMasterRequest(this), _hostAndPort);
-        if (!beginStatus.isOK()) {
-            auto cb = std::move(_refreshCallback);
-            cb(this, beginStatus);
-            return;
-        }
-
-        // If we fail during refresh, the _onFinish function of the AsyncOp will get called. As such
-        // we
-        // need to intercept those calls so we can capture them. This will get cleared out when we
-        // fill
-        // in the real onFinish in startCommand.
-        op->setOnFinish([this](RemoteCommandResponse failedResponse) {
-            invariant(!failedResponse.isOK());
-            auto cb = std::move(_refreshCallback);
-            cb(this, failedResponse.status);
-        });
-
-        op->_inRefresh = true;
-
-        _global->_impl->_asyncRunCommand(op, [this, op](std::error_code ec, size_t bytes) {
-            cancelTimeout();
-
-            auto cb = std::move(_refreshCallback);
-
-            if (ec)
-                return cb(this, Status(ErrorCodes::HostUnreachable, ec.message()));
-
-            op->_inRefresh = false;
-            cb(this, Status::OK());
-        });
-    });
-}
-
-std::unique_ptr<NetworkInterfaceASIO::AsyncOp> ASIOConnection::releaseAsyncOp() {
-    {
-        stdx::lock_guard<stdx::mutex> lk(_impl->_access->mutex);
-        _impl->_access->id++;
-    }
-    return std::move(_impl);
-}
-
-void ASIOConnection::bindAsyncOp(std::unique_ptr<NetworkInterfaceASIO::AsyncOp> op) {
-    _impl = std::move(op);
-}
-
-ASIOImpl::ASIOImpl(NetworkInterfaceASIO* impl) : _impl(impl) {}
-
-Date_t ASIOImpl::now() {
-    return _impl->now();
-}
-
-std::unique_ptr<ConnectionPool::TimerInterface> ASIOImpl::makeTimer() {
-    return stdx::make_unique<ASIOTimer>(&_impl->_strand);
-}
-
-std::shared_ptr<ConnectionPool::ConnectionInterface> ASIOImpl::makeConnection(
-    const HostAndPort& hostAndPort, size_t generation) {
-    return std::make_shared<ASIOConnection>(hostAndPort, generation, this);
-}
-
-}  // namespace connection_pool_asio
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/connection_pool_asio.h b/src/mongo/executor/connection_pool_asio.h
deleted file mode 100644
index 9bb1cae50f5..00000000000
--- a/src/mongo/executor/connection_pool_asio.h
+++ /dev/null
@@ -1,138 +0,0 @@
-/** *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include <asio/system_timer.hpp>
-
-#include <memory>
-
-#include "mongo/executor/async_stream_interface.h"
-#include "mongo/executor/connection_pool.h"
-#include "mongo/executor/network_interface.h"
-#include "mongo/executor/network_interface_asio.h"
-#include "mongo/stdx/mutex.h"
-
-namespace mongo {
-namespace executor {
-namespace connection_pool_asio {
-
-/**
- * Implements connection pool timers on top of asio
- */
-class ASIOTimer final : public ConnectionPool::TimerInterface {
-public:
-    using clock_type = asio::system_timer::clock_type;
-
-    ASIOTimer(asio::io_service::strand* strand);
-    ~ASIOTimer();
-
-    void setTimeout(Milliseconds timeout, TimeoutCallback cb) override;
-    void cancelTimeout() override;
-
-private:
-    struct CallbackSharedState {
-        stdx::mutex mutex;
-        std::size_t id = 0;
-    };
-
-    TimeoutCallback _cb;
-    asio::io_service::strand* const _strand;
-    asio::basic_waitable_timer<clock_type> _impl;
-    std::shared_ptr<CallbackSharedState> _callbackSharedState;
-};
-
-/**
- * Implements connection pool connections on top of asio
- *
- * Owns an async op when it's out of the pool
- */
-class ASIOConnection final : public ConnectionPool::ConnectionInterface {
-public:
-    ASIOConnection(const HostAndPort& hostAndPort, size_t generation, ASIOImpl* global);
-    ~ASIOConnection();
-
-    void indicateSuccess() override;
-    void indicateUsed() override;
-    void indicateFailure(Status status) override;
-    const HostAndPort& getHostAndPort() const override;
-
-    std::unique_ptr<NetworkInterfaceASIO::AsyncOp> releaseAsyncOp();
-    void bindAsyncOp(std::unique_ptr<NetworkInterfaceASIO::AsyncOp> op);
-
-    bool isHealthy() override;
-
-private:
-    Date_t getLastUsed() const override;
-    const Status& getStatus() const override;
-
-    void setTimeout(Milliseconds timeout, TimeoutCallback cb) override;
-    void cancelTimeout() override;
-
-    void setup(Milliseconds timeout, SetupCallback cb) override;
-    void resetToUnknown() override;
-    void refresh(Milliseconds timeout, RefreshCallback cb) override;
-
-    size_t getGeneration() const override;
-
-    static std::unique_ptr<NetworkInterfaceASIO::AsyncOp> makeAsyncOp(ASIOConnection* conn);
-    static Message makeIsMasterRequest(ASIOConnection* conn);
-
-private:
-    SetupCallback _setupCallback;
-    RefreshCallback _refreshCallback;
-    ASIOImpl* const _global;
-    Date_t _lastUsed;
-    Status _status = ConnectionPool::kConnectionStateUnknown;
-    HostAndPort _hostAndPort;
-    size_t _generation;
-    std::unique_ptr<NetworkInterfaceASIO::AsyncOp> _impl;
-    ASIOTimer _timer;
-};
-
-/**
- * Implementions connection pool implementation for asio
- */
-class ASIOImpl final : public ConnectionPool::DependentTypeFactoryInterface {
-    friend class ASIOConnection;
-
-public:
-    ASIOImpl(NetworkInterfaceASIO* impl);
-
-    std::shared_ptr<ConnectionPool::ConnectionInterface> makeConnection(
-        const HostAndPort& hostAndPort, size_t generation) override;
-    std::unique_ptr<ConnectionPool::TimerInterface> makeTimer() override;
-
-    Date_t now() override;
-
-private:
-    NetworkInterfaceASIO* const _impl;
-};
-
-}  // namespace connection_pool_asio
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/connection_pool_asio_integration_test.cpp b/src/mongo/executor/connection_pool_asio_integration_test.cpp
deleted file mode 100644
index 9db13ae302e..00000000000
--- a/src/mongo/executor/connection_pool_asio_integration_test.cpp
+++ /dev/null
@@ -1,341 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/connection_pool_asio.h"
-
-#include "mongo/client/connection_string.h"
-#include "mongo/executor/async_stream_factory.h"
-#include "mongo/executor/async_timer_asio.h"
-#include "mongo/executor/connection_pool_stats.h"
-#include "mongo/executor/network_connection_hook.h"
-#include "mongo/executor/network_interface_asio_test_utils.h"
-#include "mongo/rpc/get_status_from_command_result.h"
-#include "mongo/stdx/future.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/unittest/integration_test.h"
-#include "mongo/unittest/unittest.h"
-#include "mongo/util/fail_point_service.h"
-#include "mongo/util/scopeguard.h"
-#include "mongo/util/time_support.h"
-
-namespace mongo {
-namespace executor {
-namespace {
-
-class MyNetworkConnectionHook : public NetworkConnectionHook {
-public:
-    Status validateHost(const HostAndPort& remoteHost,
-                        const RemoteCommandResponse& isMasterReply) override {
-        stdx::unique_lock<stdx::mutex> lk(_mutex);
-
-        _count++;
-
-        return Status::OK();
-    }
-
-    StatusWith<boost::optional<RemoteCommandRequest>> makeRequest(
-        const HostAndPort& remoteHost) override {
-        return StatusWith<boost::optional<RemoteCommandRequest>>(boost::none);
-    }
-
-    Status handleReply(const HostAndPort& remoteHost, RemoteCommandResponse&& response) override {
-        MONGO_UNREACHABLE;
-    }
-
-    static int count() {
-        stdx::unique_lock<stdx::mutex> lk(_mutex);
-
-        return _count;
-    }
-
-private:
-    static stdx::mutex _mutex;
-    static int _count;
-};
-
-stdx::mutex MyNetworkConnectionHook::_mutex;
-int MyNetworkConnectionHook::_count = 0;
-
-TEST(ConnectionPoolASIO, TestPing) {
-    auto fixture = unittest::getFixtureConnectionString();
-
-    NetworkInterfaceASIO::Options options;
-    options.streamFactory = stdx::make_unique<AsyncStreamFactory>();
-    options.networkConnectionHook = stdx::make_unique<MyNetworkConnectionHook>();
-    options.connectionPoolOptions.maxConnections = 10;
-    options.timerFactory = stdx::make_unique<AsyncTimerFactoryASIO>();
-    NetworkInterfaceASIO net{std::move(options)};
-
-    net.startup();
-    auto guard = MakeGuard([&] { net.shutdown(); });
-
-    const int N = 50;
-
-    std::array<stdx::thread, N> threads;
-
-    for (auto& thread : threads) {
-        thread = stdx::thread([&net, &fixture]() {
-            auto status = Status::OK();
-            Deferred<RemoteCommandResponse> deferred;
-
-            RemoteCommandRequest request{
-                fixture.getServers()[0], "admin", BSON("ping" << 1), BSONObj(), nullptr};
-            net.startCommand(
-                   makeCallbackHandle(),
-                   request,
-                   [&deferred](RemoteCommandResponse resp) { deferred.emplace(std::move(resp)); })
-                .transitional_ignore();
-
-            ASSERT_OK(deferred.get().status);
-        });
-    }
-
-    for (auto&& thread : threads) {
-        thread.join();
-    }
-
-    ASSERT_LTE(MyNetworkConnectionHook::count(), 10);
-}
-
-/**
- * This test verifies a fix for SERVER-22391, where we raced if a new request
- * came in at the same time a host timeout was triggering.
- */
-TEST(ConnectionPoolASIO, TestHostTimeoutRace) {
-    auto fixture = unittest::getFixtureConnectionString();
-
-    NetworkInterfaceASIO::Options options;
-    options.streamFactory = stdx::make_unique<AsyncStreamFactory>();
-    options.connectionPoolOptions.hostTimeout = Milliseconds(1);
-    options.timerFactory = stdx::make_unique<AsyncTimerFactoryASIO>();
-    NetworkInterfaceASIO net{std::move(options)};
-
-    net.startup();
-    auto guard = MakeGuard([&] { net.shutdown(); });
-
-    for (int i = 0; i < 1000; i++) {
-        Deferred<RemoteCommandResponse> deferred;
-        RemoteCommandRequest request{
-            fixture.getServers()[0], "admin", BSON("ping" << 1), BSONObj(), nullptr};
-        net.startCommand(makeCallbackHandle(),
-                         request,
-                         [&](RemoteCommandResponse resp) { deferred.emplace(std::move(resp)); })
-            .transitional_ignore();
-
-        ASSERT_OK(deferred.get().status);
-        sleepmillis(1);
-    }
-}
-
-
-/**
- * Verify that a connections that timeout immediately don't invariant.
- */
-TEST(ConnectionPoolASIO, ConnSetupTimeout) {
-    auto fixture = unittest::getFixtureConnectionString();
-
-    NetworkInterfaceASIO::Options options;
-    options.streamFactory = stdx::make_unique<AsyncStreamFactory>();
-    options.timerFactory = stdx::make_unique<AsyncTimerFactoryASIO>();
-    options.connectionPoolOptions.refreshTimeout = Milliseconds(-2);
-    NetworkInterfaceASIO net{std::move(options)};
-
-    net.startup();
-    auto guard = MakeGuard([&] { net.shutdown(); });
-
-    Deferred<RemoteCommandResponse> deferred;
-    RemoteCommandRequest request{
-        fixture.getServers()[0], "admin", BSON("ping" << 1), BSONObj(), nullptr};
-    net.startCommand(makeCallbackHandle(),
-                     request,
-                     [&](RemoteCommandResponse resp) { deferred.emplace(std::move(resp)); })
-        .transitional_ignore();
-
-    ASSERT_EQ(deferred.get().status.code(), ErrorCodes::NetworkInterfaceExceededTimeLimit);
-}
-
-/**
- * Verify that connection refreshes actually occur, and that they drop down the totalAvailable
- * correctly.  Verifies SERVER-25006
- */
-TEST(ConnectionPoolASIO, ConnRefreshHappens) {
-    auto fixture = unittest::getFixtureConnectionString();
-
-    NetworkInterfaceASIO::Options options;
-    options.streamFactory = stdx::make_unique<AsyncStreamFactory>();
-    options.timerFactory = stdx::make_unique<AsyncTimerFactoryASIO>();
-    options.connectionPoolOptions.refreshRequirement = Milliseconds(10);
-    NetworkInterfaceASIO net{std::move(options)};
-
-    net.startup();
-    auto guard = MakeGuard([&] { net.shutdown(); });
-
-    std::array<Deferred<RemoteCommandResponse>, 10> deferreds;
-
-    RemoteCommandRequest request{fixture.getServers()[0],
-                                 "admin",
-                                 BSON("sleep" << 1 << "lock"
-                                              << "none"
-                                              << "secs"
-                                              << 2),
-                                 BSONObj(),
-                                 nullptr};
-
-    for (auto& deferred : deferreds) {
-        net.startCommand(makeCallbackHandle(),
-                         request,
-                         [&](RemoteCommandResponse resp) { deferred.emplace(std::move(resp)); })
-            .transitional_ignore();
-    }
-
-    for (auto& deferred : deferreds) {
-        ASSERT_EQ(deferred.get().isOK(), true);
-    }
-
-    sleepmillis(1000);
-
-    ConnectionPoolStats cps;
-    net.appendConnectionStats(&cps);
-
-    ASSERT_LTE(cps.totalAvailable + cps.totalInUse, 1u);
-    ASSERT_EQ(cps.totalCreated, 10u);
-}
-
-/**
- * Verify that when a refresh fails, it doesn't trigger an invariant
- */
-TEST(ConnectionPoolASIO, ConnRefreshSurvivesFailure) {
-    auto fixture = unittest::getFixtureConnectionString();
-
-    NetworkInterfaceASIO::Options options;
-    options.streamFactory = stdx::make_unique<AsyncStreamFactory>();
-    options.timerFactory = stdx::make_unique<AsyncTimerFactoryASIO>();
-    options.connectionPoolOptions.refreshRequirement = Milliseconds(0);
-    NetworkInterfaceASIO net{std::move(options)};
-
-    net.startup();
-    auto guard = MakeGuard([&] { net.shutdown(); });
-
-    Deferred<RemoteCommandResponse> deferred;
-
-    RemoteCommandRequest request{
-        fixture.getServers()[0], "admin", BSON("ping" << 1), BSONObj(), nullptr};
-    net.startCommand(makeCallbackHandle(),
-                     request,
-                     [&](RemoteCommandResponse resp) { deferred.emplace(std::move(resp)); })
-        .transitional_ignore();
-
-    deferred.get();
-
-    getGlobalFailPointRegistry()
-        ->getFailPoint("NetworkInterfaceASIOasyncRunCommandFail")
-        ->setMode(FailPoint::nTimes, 1);
-
-    sleepmillis(1000);
-
-    ConnectionPoolStats cps;
-    net.appendConnectionStats(&cps);
-
-    ASSERT_EQ(cps.totalAvailable, 0u);
-    ASSERT_EQ(cps.totalCreated, 1u);
-}
-
-/**
- * Tests that thrashing the timer while calls to setup are occurring doesn't crash.  This could
- * occur if a setup connection goes through, but the timer thread is too over-worked to cancel the
- * timers before they're invoked
- */
-TEST(ConnectionPoolASIO, ConnSetupSurvivesFailure) {
-    const int kNumThreads = 8;
-    const int kNumOps = 1000;
-
-    auto fixture = unittest::getFixtureConnectionString();
-
-    NetworkInterfaceASIO::Options options;
-    options.streamFactory = stdx::make_unique<AsyncStreamFactory>();
-    options.timerFactory = stdx::make_unique<AsyncTimerFactoryASIO>();
-    options.connectionPoolOptions.refreshTimeout = Seconds(1);
-    options.connectionPoolOptions.maxConnections = kNumThreads;
-    NetworkInterfaceASIO net{std::move(options)};
-
-    net.startup();
-    auto guard = MakeGuard([&] { net.shutdown(); });
-
-    AtomicWord<size_t> unfinished(kNumThreads * kNumOps);
-    AtomicWord<size_t> unstarted(kNumThreads * kNumOps);
-
-    std::array<stdx::thread, kNumThreads> threads;
-    stdx::mutex mutex;
-    stdx::condition_variable condvar;
-
-    for (auto& thread : threads) {
-        thread = stdx::thread([&] {
-            for (int i = 0; i < kNumOps; i++) {
-                RemoteCommandRequest request{fixture.getServers()[0],
-                                             "admin",
-                                             BSON("sleep" << 1 << "lock"
-                                                          << "none"
-                                                          << "secs"
-                                                          << 3),
-                                             BSONObj(),
-                                             nullptr};
-                net.startCommand(makeCallbackHandle(),
-                                 request,
-                                 [&](RemoteCommandResponse resp) {
-                                     if (!unfinished.subtractAndFetch(1)) {
-                                         condvar.notify_one();
-                                     }
-                                 })
-                    .transitional_ignore();
-                unstarted.subtractAndFetch(1);
-            }
-        });
-    }
-
-    stdx::thread timerThrasher([&] {
-        while (unstarted.load()) {
-            net.setAlarm(Date_t::now() + Seconds(1), [] {}).transitional_ignore();
-        }
-    });
-
-
-    for (auto& thread : threads) {
-        thread.join();
-    }
-
-    stdx::unique_lock<stdx::mutex> lk(mutex);
-    condvar.wait(lk, [&] { return !unfinished.load(); });
-
-    timerThrasher.join();
-}
-
-}  // namespace
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/network_connection_hook.h b/src/mongo/executor/network_connection_hook.h
index f76eed79b2e..993adcd1798 100644
--- a/src/mongo/executor/network_connection_hook.h
+++ b/src/mongo/executor/network_connection_hook.h
@@ -30,6 +30,8 @@
 
 #include <boost/optional.hpp>
 
+#include "mongo/bson/bsonobj.h"
+
 namespace mongo {
 
 class Status;
@@ -65,6 +67,7 @@ public:
      * std::terminate.
      */
     virtual Status validateHost(const HostAndPort& remoteHost,
+                                const BSONObj& isMasterRequest,
                                 const RemoteCommandResponse& isMasterReply) = 0;
 
     /**
diff --git a/src/mongo/executor/network_interface.cpp b/src/mongo/executor/network_interface.cpp
index e19e9284a13..3bf3cb8445b 100644
--- a/src/mongo/executor/network_interface.cpp
+++ b/src/mongo/executor/network_interface.cpp
@@ -41,6 +41,8 @@ const unsigned int NetworkInterface::kMessagingPortKeepOpen;
 NetworkInterface::NetworkInterface() {}
 NetworkInterface::~NetworkInterface() {}
 
+MONGO_FP_DECLARE(networkInterfaceDiscardCommandsBeforeAcquireConn);
+MONGO_FP_DECLARE(networkInterfaceDiscardCommandsAfterAcquireConn);
 
 }  // namespace executor
 }  // namespace mongo
diff --git a/src/mongo/executor/network_interface.h b/src/mongo/executor/network_interface.h
index b333813df14..eb740416596 100644
--- a/src/mongo/executor/network_interface.h
+++ b/src/mongo/executor/network_interface.h
@@ -35,6 +35,7 @@
 #include "mongo/executor/task_executor.h"
 #include "mongo/stdx/functional.h"
 #include "mongo/transport/baton.h"
+#include "mongo/util/fail_point_service.h"
 #include "mongo/util/future.h"
 
 namespace mongo {
@@ -43,6 +44,9 @@ class BSONObjBuilder;
 
 namespace executor {
 
+MONGO_FP_FORWARD_DECLARE(networkInterfaceDiscardCommandsBeforeAcquireConn);
+MONGO_FP_FORWARD_DECLARE(networkInterfaceDiscardCommandsAfterAcquireConn);
+
 /**
  * Interface to networking for use by TaskExecutor implementations.
  */
@@ -119,6 +123,18 @@ public:
      */
     virtual std::string getHostName() = 0;
 
+    struct Counters {
+        uint64_t canceled = 0;
+        uint64_t timedOut = 0;
+        uint64_t failed = 0;
+        uint64_t succeeded = 0;
+    };
+    /*
+     * Returns a copy of the operation counters (see struct Counters above). This method should
+     * only be used in tests, and will invariant if getTestCommands() returns false.
+     */
+    virtual Counters getCounters() const = 0;
+
     /**
      * Starts asynchronous execution of the command described by "request".
      *
diff --git a/src/mongo/executor/network_interface_asio.cpp b/src/mongo/executor/network_interface_asio.cpp
deleted file mode 100644
index 7eabcfbb71e..00000000000
--- a/src/mongo/executor/network_interface_asio.cpp
+++ /dev/null
@@ -1,527 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/network_interface_asio.h"
-
-#include <asio/system_timer.hpp>
-
-#include <utility>
-
-#include "mongo/executor/async_stream_factory.h"
-#include "mongo/executor/async_stream_interface.h"
-#include "mongo/executor/async_timer_asio.h"
-#include "mongo/executor/async_timer_interface.h"
-#include "mongo/executor/async_timer_mock.h"
-#include "mongo/executor/connection_pool_asio.h"
-#include "mongo/executor/connection_pool_stats.h"
-#include "mongo/rpc/metadata/metadata_hook.h"
-#include "mongo/stdx/chrono.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/util/concurrency/idle_thread_block.h"
-#include "mongo/util/concurrency/thread_name.h"
-#include "mongo/util/log.h"
-#include "mongo/util/net/socket_utils.h"
-#include "mongo/util/net/ssl_manager.h"
-#include "mongo/util/table_formatter.h"
-#include "mongo/util/time_support.h"
-
-namespace mongo {
-namespace executor {
-
-namespace {
-const std::size_t kIOServiceWorkers = 1;
-}  // namespace
-
-NetworkInterfaceASIO::Options::Options() = default;
-
-NetworkInterfaceASIO::NetworkInterfaceASIO(Options options)
-    : _options(std::move(options)),
-      _io_service(),
-      _metadataHook(std::move(_options.metadataHook)),
-      _hook(std::move(_options.networkConnectionHook)),
-      _state(State::kReady),
-      _timerFactory(std::move(_options.timerFactory)),
-      _streamFactory(std::move(_options.streamFactory)),
-      _connectionPool(stdx::make_unique<connection_pool_asio::ASIOImpl>(this),
-                      _options.instanceName,
-                      _options.connectionPoolOptions),
-      _isExecutorRunnable(false),
-      _strand(_io_service) {
-    invariant(_timerFactory);
-}
-
-std::string NetworkInterfaceASIO::getDiagnosticString() {
-    stdx::lock_guard<stdx::mutex> lk(_inProgressMutex);
-    return _getDiagnosticString_inlock(nullptr);
-}
-
-std::string NetworkInterfaceASIO::_getDiagnosticString_inlock(AsyncOp* currentOp) {
-    str::stream output;
-    std::vector<TableRow> rows;
-
-    output << "\nNetworkInterfaceASIO Operations' Diagnostic:\n";
-    rows.push_back({"Operation:", "Count:"});
-    rows.push_back({"Connecting", std::to_string(_inGetConnection.size())});
-    rows.push_back({"In Progress", std::to_string(_inProgress.size())});
-    rows.push_back({"Succeeded", std::to_string(getNumSucceededOps())});
-    rows.push_back({"Canceled", std::to_string(getNumCanceledOps())});
-    rows.push_back({"Failed", std::to_string(getNumFailedOps())});
-    rows.push_back({"Timed Out", std::to_string(getNumTimedOutOps())});
-    output << toTable(rows);
-
-    if (_inProgress.size() > 0) {
-        rows.clear();
-        rows.push_back(AsyncOp::kFieldLabels);
-
-        // Push AsyncOps
-        for (auto&& kv : _inProgress) {
-            auto row = kv.first->getStringFields();
-            if (currentOp) {
-                // If this is the AsyncOp we blew up on, mark with an asterisk
-                if (*currentOp == *(kv.first)) {
-                    row[0] = "*";
-                }
-            }
-
-            rows.push_back(row);
-        }
-
-        // Format as a table
-        output << "\n" << toTable(rows);
-    }
-
-    output << "\n";
-
-    return output;
-}
-
-uint64_t NetworkInterfaceASIO::getNumCanceledOps() {
-    return _numCanceledOps.load();
-}
-
-uint64_t NetworkInterfaceASIO::getNumFailedOps() {
-    return _numFailedOps.load();
-}
-
-uint64_t NetworkInterfaceASIO::getNumSucceededOps() {
-    return _numSucceededOps.load();
-}
-
-uint64_t NetworkInterfaceASIO::getNumTimedOutOps() {
-    return _numTimedOutOps.load();
-}
-
-void NetworkInterfaceASIO::appendConnectionStats(ConnectionPoolStats* stats) const {
-    _connectionPool.appendConnectionStats(stats);
-}
-
-std::string NetworkInterfaceASIO::getHostName() {
-    return getHostNameCached();
-}
-
-void NetworkInterfaceASIO::startup() {
-    _serviceRunners.resize(kIOServiceWorkers);
-    for (std::size_t i = 0; i < kIOServiceWorkers; ++i) {
-        _serviceRunners[i] = stdx::thread([this, i]() {
-            setThreadName(_options.instanceName + "-" + std::to_string(i));
-            try {
-                LOG(2) << "The NetworkInterfaceASIO worker thread is spinning up";
-                asio::io_service::work work(_io_service);
-                std::error_code ec;
-                _io_service.run(ec);
-                if (ec) {
-                    severe() << "Failure in _io_service.run(): " << ec.message();
-                    fassertFailed(40335);
-                }
-            } catch (...) {
-                severe() << "Uncaught exception in NetworkInterfaceASIO IO "
-                            "worker thread of type: "
-                         << exceptionToStatus();
-                fassertFailed(28820);
-            }
-        });
-    };
-    _state.store(State::kRunning);
-}
-
-void NetworkInterfaceASIO::shutdown() {
-    _state.store(State::kShutdown);
-    _io_service.stop();
-    for (auto&& worker : _serviceRunners) {
-        worker.join();
-    }
-    LOG(2) << "NetworkInterfaceASIO shutdown successfully";
-}
-
-void NetworkInterfaceASIO::waitForWork() {
-    stdx::unique_lock<stdx::mutex> lk(_executorMutex);
-    // TODO: This can be restructured with a lambda.
-    while (!_isExecutorRunnable) {
-        MONGO_IDLE_THREAD_BLOCK;
-        _isExecutorRunnableCondition.wait(lk);
-    }
-    _isExecutorRunnable = false;
-}
-
-void NetworkInterfaceASIO::waitForWorkUntil(Date_t when) {
-    stdx::unique_lock<stdx::mutex> lk(_executorMutex);
-    // TODO: This can be restructured with a lambda.
-    while (!_isExecutorRunnable) {
-        const Milliseconds waitTime(when - now());
-        if (waitTime <= Milliseconds(0)) {
-            break;
-        }
-        MONGO_IDLE_THREAD_BLOCK;
-        _isExecutorRunnableCondition.wait_for(lk, waitTime.toSystemDuration());
-    }
-    _isExecutorRunnable = false;
-}
-
-void NetworkInterfaceASIO::signalWorkAvailable() {
-    stdx::unique_lock<stdx::mutex> lk(_executorMutex);
-    _signalWorkAvailable_inlock();
-}
-
-void NetworkInterfaceASIO::_signalWorkAvailable_inlock() {
-    if (!_isExecutorRunnable) {
-        _isExecutorRunnable = true;
-        _isExecutorRunnableCondition.notify_one();
-    }
-}
-
-Date_t NetworkInterfaceASIO::now() {
-    return _timerFactory->now();
-}
-
-namespace {
-
-Status attachMetadataIfNeeded(RemoteCommandRequest& request,
-                              rpc::EgressMetadataHook* metadataHook) {
-
-    // Append the metadata of the request with metadata from the metadata hook
-    // if a hook is installed
-    if (metadataHook) {
-        BSONObjBuilder augmentedBob(std::move(request.metadata));
-
-        auto writeStatus = callNoexcept(*metadataHook,
-                                        &rpc::EgressMetadataHook::writeRequestMetadata,
-                                        request.opCtx,
-                                        &augmentedBob);
-        if (!writeStatus.isOK()) {
-            return writeStatus;
-        }
-
-        request.metadata = augmentedBob.obj();
-    }
-
-    return Status::OK();
-}
-
-}  // namespace
-
-Status NetworkInterfaceASIO::startCommand(const TaskExecutor::CallbackHandle& cbHandle,
-                                          RemoteCommandRequest& request,
-                                          const RemoteCommandCompletionFn& onFinish,
-                                          const transport::BatonHandle& baton) {
-    MONGO_ASIO_INVARIANT(onFinish, "Invalid completion function");
-    {
-        stdx::lock_guard<stdx::mutex> lk(_inProgressMutex);
-        const auto insertResult = _inGetConnection.emplace(cbHandle);
-        // We should never see the same CallbackHandle added twice
-        MONGO_ASIO_INVARIANT_INLOCK(insertResult.second, "Same CallbackHandle added twice");
-    }
-
-    if (inShutdown()) {
-        return {ErrorCodes::ShutdownInProgress, "NetworkInterfaceASIO shutdown in progress"};
-    }
-
-    LOG(2) << "startCommand: " << redact(request.toString());
-
-    auto getConnectionStartTime = now();
-
-    auto statusMetadata = attachMetadataIfNeeded(request, _metadataHook.get());
-    if (!statusMetadata.isOK()) {
-        return statusMetadata;
-    }
-
-    auto nextStep = [this, getConnectionStartTime, cbHandle, request, onFinish](
-        StatusWith<ConnectionPool::ConnectionHandle> swConn) {
-
-        if (!swConn.isOK()) {
-            LOG(2) << "Failed to get connection from pool for request " << request.id << ": "
-                   << swConn.getStatus();
-
-            bool wasPreviouslyCanceled = false;
-            {
-                stdx::lock_guard<stdx::mutex> lk(_inProgressMutex);
-                wasPreviouslyCanceled = _inGetConnection.erase(cbHandle) == 0;
-            }
-
-            Status status = wasPreviouslyCanceled
-                ? Status(ErrorCodes::CallbackCanceled, "Callback canceled")
-                : swConn.getStatus();
-            if (ErrorCodes::isExceededTimeLimitError(status.code())) {
-                _numTimedOutOps.fetchAndAdd(1);
-            }
-            if (status.code() != ErrorCodes::CallbackCanceled) {
-                _numFailedOps.fetchAndAdd(1);
-            }
-
-            onFinish({status, now() - getConnectionStartTime});
-            signalWorkAvailable();
-            return;
-        }
-
-        auto conn = static_cast<connection_pool_asio::ASIOConnection*>(swConn.getValue().get());
-
-        AsyncOp* op = nullptr;
-
-        stdx::unique_lock<stdx::mutex> lk(_inProgressMutex);
-
-        const auto eraseCount = _inGetConnection.erase(cbHandle);
-
-        // If we didn't find the request, we've been canceled
-        if (eraseCount == 0) {
-            lk.unlock();
-
-            onFinish({ErrorCodes::CallbackCanceled,
-                      "Callback canceled",
-                      now() - getConnectionStartTime});
-
-            // Though we were canceled, we know that the stream is fine, so indicate success.
-            conn->indicateSuccess();
-
-            signalWorkAvailable();
-
-            return;
-        }
-
-        // We can't release the AsyncOp until we know we were not canceled.
-        auto ownedOp = conn->releaseAsyncOp();
-        op = ownedOp.get();
-
-        // This AsyncOp may be recycled. We expect timeout and canceled to be clean.
-        // If this op was most recently used to connect, its state transitions won't have been
-        // reset, so we do that here.
-        MONGO_ASIO_INVARIANT_INLOCK(!op->canceled(), "AsyncOp has dirty canceled flag", op);
-        MONGO_ASIO_INVARIANT_INLOCK(!op->timedOut(), "AsyncOp has dirty timeout flag", op);
-        op->clearStateTransitions();
-
-        // Now that we're inProgress, an external cancel can touch our op, but
-        // not until we release the inProgressMutex.
-        _inProgress.emplace(op, std::move(ownedOp));
-
-        op->_cbHandle = std::move(cbHandle);
-        op->_request = std::move(request);
-        op->_onFinish = std::move(onFinish);
-        op->_connectionPoolHandle = std::move(swConn.getValue());
-        op->startProgress(getConnectionStartTime);
-
-        // This ditches the lock and gets us onto the strand (so we're
-        // threadsafe)
-        op->_strand.post([this, op, getConnectionStartTime] {
-            const auto timeout = op->_request.timeout;
-
-            // Set timeout now that we have the correct request object
-            if (timeout != RemoteCommandRequest::kNoTimeout) {
-                // Subtract the time it took to get the connection from the pool from the request
-                // timeout.
-                auto getConnectionDuration = now() - getConnectionStartTime;
-                if (getConnectionDuration >= timeout) {
-                    // We only assume that the request timer is guaranteed to fire *after* the
-                    // timeout duration - but make no stronger assumption. It is thus possible that
-                    // we have already exceeded the timeout. In this case we timeout the operation
-                    // manually.
-                    std::stringstream msg;
-                    msg << "Remote command timed out while waiting to get a connection from the "
-                        << "pool, took " << getConnectionDuration << ", timeout was set to "
-                        << timeout;
-                    auto rs = ResponseStatus(ErrorCodes::NetworkInterfaceExceededTimeLimit,
-                                             msg.str(),
-                                             getConnectionDuration);
-                    return _completeOperation(op, rs);
-                }
-
-                // The above conditional guarantees that the adjusted timeout will never underflow.
-                MONGO_ASIO_INVARIANT(timeout > getConnectionDuration, "timeout underflowed", op);
-                const auto adjustedTimeout = timeout - getConnectionDuration;
-                const auto requestId = op->_request.id;
-
-                try {
-                    op->_timeoutAlarm =
-                        op->_owner->_timerFactory->make(&op->_strand, adjustedTimeout);
-                } catch (std::system_error& e) {
-                    severe() << "Failed to construct timer for AsyncOp: " << e.what();
-                    fassertFailed(40334);
-                }
-
-                std::shared_ptr<AsyncOp::AccessControl> access;
-                std::size_t generation;
-                {
-                    stdx::lock_guard<stdx::mutex> lk(op->_access->mutex);
-                    access = op->_access;
-                    generation = access->id;
-                }
-
-                op->_timeoutAlarm->asyncWait([op, access, generation, requestId, adjustedTimeout](
-                    std::error_code ec) {
-                    // We must pass a check for safe access before using op inside the
-                    // callback or we may attempt access on an invalid pointer.
-                    stdx::lock_guard<stdx::mutex> lk(access->mutex);
-                    if (generation != access->id) {
-                        // The operation has been cleaned up, do not access.
-                        return;
-                    }
-
-                    if (!ec) {
-                        LOG(2) << "Request " << requestId << " timed out"
-                               << ", adjusted timeout after getting connection from pool was "
-                               << adjustedTimeout << ", op was " << redact(op->toString());
-
-                        op->timeOut_inlock();
-                    } else {
-                        LOG(2) << "Failed to time request " << requestId << "out: " << ec.message()
-                               << ", op was " << redact(op->toString());
-                    }
-                });
-            }
-
-            _beginCommunication(op);
-        });
-    };
-
-    _connectionPool.get(request.target, request.timeout, nextStep);
-    return Status::OK();
-}
-
-void NetworkInterfaceASIO::cancelCommand(const TaskExecutor::CallbackHandle& cbHandle,
-                                         const transport::BatonHandle& baton) {
-    stdx::lock_guard<stdx::mutex> lk(_inProgressMutex);
-
-    // If we found a matching cbHandle in _inGetConnection, then
-    // simply removing it has the same effect as cancelling it, so we
-    // can just return.
-    if (_inGetConnection.erase(cbHandle) != 0) {
-        _numCanceledOps.fetchAndAdd(1);
-        return;
-    }
-
-    // TODO: This linear scan is unfortunate. It is here because our
-    // primary data structure is to keep the AsyncOps in an
-    // unordered_map by pointer, but here we only have the
-    // callback. We could keep two data structures at the risk of
-    // having them diverge.
-    for (auto&& kv : _inProgress) {
-        if (kv.first->cbHandle() == cbHandle) {
-            kv.first->cancel();
-            _numCanceledOps.fetchAndAdd(1);
-            break;
-        }
-    }
-}
-
-Status NetworkInterfaceASIO::setAlarm(Date_t when,
-                                      const stdx::function<void()>& action,
-                                      const transport::BatonHandle& baton) {
-    if (inShutdown()) {
-        return {ErrorCodes::ShutdownInProgress, "NetworkInterfaceASIO shutdown in progress"};
-    }
-
-    std::shared_ptr<asio::system_timer> alarm;
-
-    try {
-        auto timeLeft = when - now();
-        // "alarm" must stay alive until it expires, hence the shared_ptr.
-        alarm = std::make_shared<asio::system_timer>(_io_service, timeLeft.toSystemDuration());
-    } catch (...) {
-        return exceptionToStatus();
-    }
-
-    alarm->async_wait([alarm, this, action, when, baton](std::error_code ec) {
-        const auto nowValue = now();
-        if (nowValue < when) {
-            warning() << "ASIO alarm returned early. Expected at: " << when
-                      << ", fired at: " << nowValue;
-            const auto status = setAlarm(when, action, baton);
-            if ((!status.isOK()) && (status.code() != ErrorCodes::ShutdownInProgress)) {
-                fassertFailedWithStatus(40383, status);
-            }
-            return;
-        }
-        if (!ec) {
-            return action();
-        } else if (ec != asio::error::operation_aborted) {
-            // When the network interface is shut down, it will cancel all pending
-            // alarms, raising an "operation_aborted" error here, which we ignore.
-            warning() << "setAlarm() received an error: " << ec.message();
-        }
-    });
-
-    return Status::OK();
-};
-
-bool NetworkInterfaceASIO::inShutdown() const {
-    return (_state.load() == State::kShutdown);
-}
-
-bool NetworkInterfaceASIO::onNetworkThread() {
-    auto id = stdx::this_thread::get_id();
-    return std::any_of(_serviceRunners.begin(),
-                       _serviceRunners.end(),
-                       [id](const stdx::thread& thread) { return id == thread.get_id(); });
-}
-
-void NetworkInterfaceASIO::_failWithInfo(const char* file,
-                                         int line,
-                                         std::string error,
-                                         AsyncOp* op) {
-    stdx::lock_guard<stdx::mutex> lk(_inProgressMutex);
-    _failWithInfo_inlock(file, line, error, op);
-}
-
-void NetworkInterfaceASIO::_failWithInfo_inlock(const char* file,
-                                                int line,
-                                                std::string error,
-                                                AsyncOp* op) {
-    std::stringstream ss;
-    ss << "Invariant failure at " << file << ":" << line << ": " << error;
-    ss << _getDiagnosticString_inlock(op);
-    Status status{ErrorCodes::InternalError, ss.str()};
-    fassertFailedWithStatus(34429, status);
-}
-
-void NetworkInterfaceASIO::dropConnections(const HostAndPort& hostAndPort) {
-    _connectionPool.dropConnections(hostAndPort);
-}
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/network_interface_asio.h b/src/mongo/executor/network_interface_asio.h
deleted file mode 100644
index 3a423e8b779..00000000000
--- a/src/mongo/executor/network_interface_asio.h
+++ /dev/null
@@ -1,526 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include <asio.hpp>
-
-#include <array>
-#include <boost/optional.hpp>
-#include <memory>
-#include <string>
-#include <system_error>
-#include <vector>
-
-#include "mongo/base/status.h"
-#include "mongo/base/system_error.h"
-#include "mongo/executor/async_stream_factory_interface.h"
-#include "mongo/executor/async_stream_interface.h"
-#include "mongo/executor/async_timer_interface.h"
-#include "mongo/executor/connection_pool.h"
-#include "mongo/executor/network_connection_hook.h"
-#include "mongo/executor/network_interface.h"
-#include "mongo/executor/remote_command_request.h"
-#include "mongo/executor/remote_command_response.h"
-#include "mongo/platform/atomic_word.h"
-#include "mongo/rpc/message.h"
-#include "mongo/rpc/metadata/metadata_hook.h"
-#include "mongo/rpc/protocol.h"
-#include "mongo/stdx/condition_variable.h"
-#include "mongo/stdx/functional.h"
-#include "mongo/stdx/mutex.h"
-#include "mongo/stdx/thread.h"
-#include "mongo/stdx/unordered_map.h"
-#include "mongo/stdx/unordered_set.h"
-#include "mongo/transport/message_compressor_manager.h"
-
-namespace mongo {
-
-namespace executor {
-
-namespace connection_pool_asio {
-class ASIOConnection;
-class ASIOTimer;
-class ASIOImpl;
-}  // connection_pool_asio
-
-class AsyncStreamInterface;
-
-#define MONGO_ASIO_INVARIANT(_Expression, ...)              \
-    do {                                                    \
-        if (MONGO_unlikely(!(_Expression))) {               \
-            _failWithInfo(__FILE__, __LINE__, __VA_ARGS__); \
-        }                                                   \
-    } while (false)
-
-#define MONGO_ASIO_INVARIANT_INLOCK(_Expression, ...)              \
-    do {                                                           \
-        if (MONGO_unlikely(!(_Expression))) {                      \
-            _failWithInfo_inlock(__FILE__, __LINE__, __VA_ARGS__); \
-        }                                                          \
-    } while (false)
-
-// An AsyncOp can transition through at most 5 states.
-const int kMaxStateTransitions = 5;
-
-/**
- * Implementation of the replication system's network interface using Christopher
- * Kohlhoff's ASIO library instead of existing MongoDB networking primitives.
- */
-class NetworkInterfaceASIO final : public NetworkInterface {
-    friend class connection_pool_asio::ASIOConnection;
-    friend class connection_pool_asio::ASIOTimer;
-    friend class connection_pool_asio::ASIOImpl;
-    class AsyncOp;
-
-public:
-    struct Options {
-        Options();
-
-        std::string instanceName = "NetworkInterfaceASIO";
-        ConnectionPool::Options connectionPoolOptions;
-        std::unique_ptr<AsyncTimerFactoryInterface> timerFactory;
-        std::unique_ptr<NetworkConnectionHook> networkConnectionHook;
-        std::unique_ptr<AsyncStreamFactoryInterface> streamFactory;
-        std::unique_ptr<rpc::EgressMetadataHook> metadataHook;
-    };
-
-    NetworkInterfaceASIO(Options = Options());
-
-    std::string getDiagnosticString() override;
-
-    uint64_t getNumCanceledOps();
-    uint64_t getNumFailedOps();
-    uint64_t getNumSucceededOps();
-    uint64_t getNumTimedOutOps();
-
-    void appendConnectionStats(ConnectionPoolStats* stats) const override;
-    std::string getHostName() override;
-    void startup() override;
-    void shutdown() override;
-    bool inShutdown() const override;
-    void waitForWork() override;
-    void waitForWorkUntil(Date_t when) override;
-    void signalWorkAvailable() override;
-    Date_t now() override;
-    Status startCommand(const TaskExecutor::CallbackHandle& cbHandle,
-                        RemoteCommandRequest& request,
-                        const RemoteCommandCompletionFn& onFinish,
-                        const transport::BatonHandle& baton = nullptr) override;
-    void cancelCommand(const TaskExecutor::CallbackHandle& cbHandle,
-                       const transport::BatonHandle& baton = nullptr) override;
-    Status setAlarm(Date_t when,
-                    const stdx::function<void()>& action,
-                    const transport::BatonHandle& baton = nullptr) override;
-
-    bool onNetworkThread() override;
-
-    void dropConnections(const HostAndPort& hostAndPort) override;
-
-private:
-    using ResponseStatus = TaskExecutor::ResponseStatus;
-    using NetworkInterface::RemoteCommandCompletionFn;
-    using NetworkOpHandler = stdx::function<void(std::error_code, size_t)>;
-    using TableRow = std::vector<std::string>;
-
-    enum class State { kReady, kRunning, kShutdown };
-
-    friend class AsyncOp;
-
-    /**
-     * AsyncConnection encapsulates the per-connection state we maintain.
-     */
-    class AsyncConnection {
-    public:
-        AsyncConnection(std::unique_ptr<AsyncStreamInterface>, rpc::ProtocolSet serverProtocols);
-
-        AsyncStreamInterface& stream();
-
-        void cancel();
-
-        rpc::ProtocolSet serverProtocols() const;
-        rpc::ProtocolSet clientProtocols() const;
-        void setServerProtocols(rpc::ProtocolSet protocols);
-
-        MessageCompressorManager& getCompressorManager() {
-            return _compressorManager;
-        }
-
-    private:
-        std::unique_ptr<AsyncStreamInterface> _stream;
-
-        rpc::ProtocolSet _serverProtocols;
-
-        // Dynamically initialized from [min max]WireVersionOutgoing.
-        // Its expected that isMaster response is checked only on the caller.
-        rpc::ProtocolSet _clientProtocols{rpc::supports::kNone};
-
-        MessageCompressorManager _compressorManager;
-    };
-
-    /**
-     * AsyncCommand holds state for a currently running or soon-to-be-run command.
-     */
-    class AsyncCommand {
-    public:
-        AsyncCommand(AsyncConnection* conn,
-                     Message&& command,
-                     Date_t now,
-                     const HostAndPort& target);
-
-        NetworkInterfaceASIO::AsyncConnection& conn();
-
-        Message& toSend();
-        Message& toRecv();
-        MSGHEADER::Value& header();
-
-        ResponseStatus response(AsyncOp* op,
-                                rpc::Protocol protocol,
-                                Date_t now,
-                                rpc::EgressMetadataHook* metadataHook = nullptr);
-
-        HostAndPort target() const {
-            return this->_target;
-        }
-
-    private:
-        NetworkInterfaceASIO::AsyncConnection* const _conn;
-
-        Message _toSend;
-        Message _toRecv;
-
-        // TODO: Investigate efficiency of storing header separately.
-        MSGHEADER::Value _header;
-
-        const Date_t _start;
-
-        const HostAndPort _target;
-    };
-
-    /**
-     * Helper object to manage individual network operations.
-     */
-    class AsyncOp {
-        friend class NetworkInterfaceASIO;
-        friend class connection_pool_asio::ASIOConnection;
-
-    public:
-        /**
-          * Describe the various states through which an AsyncOp transitions.
-          */
-        enum class State : unsigned char {
-            // A non-state placeholder.
-            kNoState,
-            // A new or zeroed-out AsyncOp.
-            kUninitialized,
-            // An AsyncOp begins its progress when startProgress() is called.
-            kInProgress,
-            // An AsyncOp transitions to kTimedOut when timeOut() is called.
-            // Note that the AsyncOp can be in a kCanceled state and still be
-            // in-flight in NetworkInterfaceASIO.
-            kTimedOut,
-            // An AsyncOp transitions to kCanceled when cancel() is called.
-            // Note that the AsyncOp can be in a kCanceled state and still be
-            // in-flight in NetworkInterfaceASIO.
-            kCanceled,
-            // An AsyncOp is finished once its finish() method is called. Note
-            // that the AsyncOp can be in a kFinished state and still be in the
-            // NetworkInterface's set of in-progress operations.
-            kFinished,
-        };
-
-        AsyncOp(NetworkInterfaceASIO* net,
-                const TaskExecutor::CallbackHandle& cbHandle,
-                const RemoteCommandRequest& request,
-                const RemoteCommandCompletionFn& onFinish,
-                Date_t now);
-
-        /**
-         * Access control for AsyncOp. These objects should be used through shared_ptrs.
-         *
-         * In order to safely access an AsyncOp:
-         * 1. Take the lock
-         * 2. Check the id
-         * 3. If id matches saved generation, proceed, otherwise op has been recycled.
-         */
-        struct AccessControl {
-            stdx::mutex mutex;
-            std::size_t id = 0;
-        };
-
-        void cancel();
-        bool canceled() const;
-        void timeOut_inlock();
-        bool timedOut() const;
-
-        const TaskExecutor::CallbackHandle& cbHandle() const;
-
-        AsyncConnection& connection();
-
-        void setConnection(AsyncConnection&& conn);
-
-        // AsyncOp may run multiple commands over its lifetime (for example, an ismaster
-        // command, the command provided to the NetworkInterface via startCommand(), etc.)
-        // Calling beginCommand() resets internal state to prepare to run newCommand.
-        Status beginCommand(const RemoteCommandRequest& request);
-
-        // This form of beginCommand takes a raw message. It is needed if the caller
-        // has to form the command manually (e.g. to use a specific requestBuilder).
-        Status beginCommand(Message&& newCommand, const HostAndPort& target);
-
-        AsyncCommand& command();
-        bool commandIsInitialized() const;
-
-        void finish(TaskExecutor::ResponseStatus&& status);
-
-        const RemoteCommandRequest& request() const;
-
-        void startProgress(Date_t startTime);
-
-        Date_t start() const;
-
-        rpc::Protocol operationProtocol() const;
-
-        void setOperationProtocol(rpc::Protocol proto);
-
-        void setResponseMetadata(BSONObj m);
-        BSONObj getResponseMetadata();
-
-        void reset();
-
-        void clearStateTransitions();
-
-        void setOnFinish(RemoteCommandCompletionFn&& onFinish);
-
-        // Returns diagnostic strings for logging.
-        TableRow getStringFields() const;
-        std::string toString() const;
-
-        asio::io_service::strand& strand() {
-            return _strand;
-        }
-
-        asio::ip::tcp::resolver& resolver() {
-            return _resolver;
-        }
-
-        bool operator==(const AsyncOp& other) const;
-
-    private:
-        // Type to represent the internal id of this request.
-        using AsyncOpId = uint64_t;
-
-        static const TableRow kFieldLabels;
-
-        // Return string representation of a given state.
-        std::string _stateToString(State state) const;
-
-        // Return a string representation of this op's state transitions.
-        std::string _stateString() const;
-
-        bool _hasSeenState(State state) const;
-
-        // Track and validate AsyncOp state transitions.
-        // Use the _inlock variant if already holding the access control lock.
-        void _transitionToState(State newState);
-        void _transitionToState_inlock(State newState);
-
-        // Helper for debugging.
-        void _failWithInfo(const char* file, int line, std::string error) const;
-
-        NetworkInterfaceASIO* const _owner;
-        // Information describing a task enqueued on the NetworkInterface
-        // via a call to startCommand().
-        TaskExecutor::CallbackHandle _cbHandle;
-        RemoteCommandRequest _request;
-        RemoteCommandCompletionFn _onFinish;
-
-        // AsyncOp's have a handle to their connection pool handle. They are
-        // also owned by it when they're in the pool
-        ConnectionPool::ConnectionHandle _connectionPoolHandle;
-
-        /**
-         * The connection state used to service this request. We wrap it in an optional
-         * as it is instantiated at some point after the AsyncOp is created.
-         */
-        boost::optional<AsyncConnection> _connection;
-
-        /**
-         * The RPC protocol used for this operation. We wrap it in an optional as it
-         * is not known until we obtain a connection.
-         */
-        boost::optional<rpc::Protocol> _operationProtocol;
-
-        Date_t _start;
-        std::unique_ptr<AsyncTimerInterface> _timeoutAlarm;
-
-        asio::ip::tcp::resolver _resolver;
-
-        const AsyncOpId _id;
-
-        /**
-         * We maintain a shared_ptr to an access control object. This ensures that tangent
-         * execution paths, such as timeouts for this operation, will not try to access its
-         * state after it has been cleaned up.
-         */
-        std::shared_ptr<AccessControl> _access;
-
-        /**
-         * An AsyncOp may run 0, 1, or multiple commands over its lifetime.
-         * AsyncOp only holds at most a single AsyncCommand object at a time,
-         * representing its current running or next-to-be-run command, if there is one.
-         */
-        boost::optional<AsyncCommand> _command;
-        bool _inSetup;
-        bool _inRefresh;
-
-        /**
-         * The explicit strand that all operations for this op must run on.
-         * This must be the last member of AsyncOp because any pending
-         * operation for the strand are run when it's dtor is called. Any
-         * members that fall after it will have already been destroyed, which
-         * will make those fields illegal to touch from callbacks.
-         */
-        asio::io_service::strand _strand;
-
-        /**
-         * We hold an array of states to show the path this AsyncOp has taken.
-         * Must be holding the access control's lock to edit.
-         */
-        std::array<State, kMaxStateTransitions> _states;
-
-        BSONObj _responseMetadata{};
-    };
-
-    void _startCommand(AsyncOp* op);
-
-    /**
-     * Wraps a completion handler in pre-condition checks.
-     * When we resume after an asynchronous call, we may find the following:
-     *    - the AsyncOp has been canceled in the interim (via cancelCommand())
-     *    - the asynchronous call has returned a non-OK error code
-     * Should both conditions be present, we handle cancelation over errors. States use
-     * _validateAndRun() to perform these checks before advancing the state machine.
-     */
-    template <typename Handler>
-    void _validateAndRun(AsyncOp* op, std::error_code ec, Handler&& handler) {
-        if (op->canceled()) {
-            auto rs = ResponseStatus(
-                ErrorCodes::CallbackCanceled, "Callback canceled", now() - op->start());
-            return _completeOperation(op, rs);
-        } else if (op->timedOut()) {
-            auto rs = ResponseStatus(ErrorCodes::NetworkInterfaceExceededTimeLimit,
-                                     "Operation timed out",
-                                     now() - op->start());
-            return _completeOperation(op, rs);
-        } else if (ec)
-            return _networkErrorCallback(op, ec);
-
-        handler();
-    }
-
-    // Connection
-    void _connect(AsyncOp* op);
-
-    // setup plaintext TCP socket
-    void _setupSocket(AsyncOp* op, asio::ip::tcp::resolver::iterator endpoints);
-
-    void _runIsMaster(AsyncOp* op);
-    void _runConnectionHook(AsyncOp* op);
-    void _authenticate(AsyncOp* op);
-
-    // Communication state machine
-    void _beginCommunication(AsyncOp* op);
-    void _completedOpCallback(AsyncOp* op);
-    void _networkErrorCallback(AsyncOp* op, const std::error_code& ec);
-    void _completeOperation(AsyncOp* op, TaskExecutor::ResponseStatus resp);
-
-    void _signalWorkAvailable_inlock();
-
-    void _asyncRunCommand(AsyncOp* op, NetworkOpHandler handler);
-
-    std::string _getDiagnosticString_inlock(AsyncOp* currentOp);
-
-    // Helpers for debugging crashes
-    void _failWithInfo(const char* file, int line, std::string error, AsyncOp* op = nullptr);
-    void _failWithInfo_inlock(const char* file, int line, std::string error, AsyncOp* op = nullptr);
-
-    Options _options;
-
-    asio::io_service _io_service;
-    std::vector<stdx::thread> _serviceRunners;
-
-    const std::unique_ptr<rpc::EgressMetadataHook> _metadataHook;
-
-    const std::unique_ptr<NetworkConnectionHook> _hook;
-
-    std::atomic<State> _state;  // NOLINT
-
-    std::unique_ptr<AsyncTimerFactoryInterface> _timerFactory;
-
-    std::unique_ptr<AsyncStreamFactoryInterface> _streamFactory;
-
-    ConnectionPool _connectionPool;
-
-    // If it is necessary to hold this lock while accessing a particular operation with
-    // an AccessControl object, take this lock first, always.
-    stdx::mutex _inProgressMutex;
-    stdx::unordered_map<AsyncOp*, std::unique_ptr<AsyncOp>> _inProgress;
-    stdx::unordered_set<TaskExecutor::CallbackHandle> _inGetConnection;
-
-    // Operation counters
-    AtomicUInt64 _numCanceledOps;
-    AtomicUInt64 _numFailedOps;  // includes timed out ops but does not include canceled ops
-    AtomicUInt64 _numSucceededOps;
-    AtomicUInt64 _numTimedOutOps;
-
-    stdx::mutex _executorMutex;
-    bool _isExecutorRunnable;
-    stdx::condition_variable _isExecutorRunnableCondition;
-
-    /**
-     * The explicit strand that all non-op operations run on. This must be the
-     * last member of NetworkInterfaceASIO because any pending operation for
-     * the strand are run when it's dtor is called. Any members that fall after
-     * it will have already been destroyed, which will make those fields
-     * illegal to touch from callbacks.
-     */
-    asio::io_service::strand _strand;
-};
-
-template <typename T, typename R, typename... MethodArgs, typename... DeducedArgs>
-R callNoexcept(T& obj, R (T::*method)(MethodArgs...), DeducedArgs&&... args) {
-    try {
-        return (obj.*method)(std::forward<DeducedArgs>(args)...);
-    } catch (...) {
-        std::terminate();
-    }
-}
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/network_interface_asio_auth.cpp b/src/mongo/executor/network_interface_asio_auth.cpp
deleted file mode 100644
index 1a981b3d017..00000000000
--- a/src/mongo/executor/network_interface_asio_auth.cpp
+++ /dev/null
@@ -1,232 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/network_interface_asio.h"
-
-#include "mongo/bson/util/builder.h"
-#include "mongo/client/authenticate.h"
-#include "mongo/config.h"
-#include "mongo/db/auth/authorization_manager_global.h"
-#include "mongo/db/auth/internal_user_auth.h"
-#include "mongo/db/commands.h"
-#include "mongo/db/commands/test_commands_enabled.h"
-#include "mongo/db/server_options.h"
-#include "mongo/db/wire_version.h"
-#include "mongo/rpc/factory.h"
-#include "mongo/rpc/get_status_from_command_result.h"
-#include "mongo/rpc/legacy_request_builder.h"
-#include "mongo/rpc/metadata/client_metadata.h"
-#include "mongo/rpc/reply_interface.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/util/log.h"
-#include "mongo/util/net/ssl_manager.h"
-#include "mongo/util/version.h"
-
-namespace mongo {
-namespace executor {
-
-using ResponseStatus = TaskExecutor::ResponseStatus;
-
-void NetworkInterfaceASIO::_runIsMaster(AsyncOp* op) {
-    BSONObjBuilder bob;
-    bob.append("isMaster", 1);
-    bob.append("hangUpOnStepDown", false);
-
-    const auto versionString = VersionInfoInterface::instance().version();
-    ClientMetadata::serialize(_options.instanceName, versionString, &bob);
-
-    if (getTestCommandsEnabled()) {
-        // Only include the host:port of this process in the isMaster command request if test
-        // commands are enabled. mongobridge uses this field to identify the process opening a
-        // connection to it.
-        StringBuilder sb;
-        sb << getHostName() << ':' << serverGlobalParams.port;
-        bob.append("hostInfo", sb.str());
-    }
-
-    op->connection().getCompressorManager().clientBegin(&bob);
-
-    if (WireSpec::instance().isInternalClient) {
-        WireSpec::appendInternalClientWireVersion(WireSpec::instance().outgoing, &bob);
-    }
-
-    // We use a legacy request to create our ismaster request because we may
-    // have to communicate with servers that do not support other protocols.
-    auto isMasterRequest =
-        rpc::legacyRequestFromOpMsgRequest(OpMsgRequest::fromDBAndBody("admin", bob.obj()));
-
-    // Set current command to ismaster request and run
-    auto beginStatus = op->beginCommand(std::move(isMasterRequest), op->request().target);
-    if (!beginStatus.isOK()) {
-        return _completeOperation(op, beginStatus);
-    }
-
-    // Callback to parse protocol information out of received ismaster response
-    auto parseIsMaster = [this, op]() {
-
-        auto swCommandReply = op->command().response(op, rpc::Protocol::kOpQuery, now());
-        if (!swCommandReply.isOK()) {
-            return _completeOperation(op, swCommandReply);
-        }
-
-        auto commandReply = std::move(swCommandReply);
-
-        // Ensure that the isMaster response is "ok:1".
-        auto commandStatus = getStatusFromCommandResult(commandReply.data);
-        if (!commandStatus.isOK()) {
-            return _completeOperation(op, commandStatus);
-        }
-
-        auto protocolSet = rpc::parseProtocolSetFromIsMasterReply(commandReply.data);
-        if (!protocolSet.isOK())
-            return _completeOperation(op, protocolSet.getStatus());
-
-        auto validateStatus =
-            rpc::validateWireVersion(WireSpec::instance().outgoing, protocolSet.getValue().version);
-        if (!validateStatus.isOK()) {
-            warning() << "remote host has incompatible wire version: " << validateStatus;
-
-            return _completeOperation(op, validateStatus);
-        }
-        auto egressTagManager = _options.connectionPoolOptions.egressTagCloserManager;
-        if (egressTagManager) {
-            // Tag outgoing connection so it can be kept open on FCV upgrade if it is not to a
-            // server with a lower binary version.
-            if (protocolSet.getValue().version.maxWireVersion >=
-                WireSpec::instance().outgoing.maxWireVersion) {
-                egressTagManager->mutateTags(
-                    op->command().target(),
-                    [](transport::Session::TagMask tags) { return transport::Session::kKeepOpen; });
-            }
-        }  // Some unit and integration tests do not set up an egress tag manager.
-
-        op->connection().setServerProtocols(protocolSet.getValue().protocolSet);
-
-        invariant(op->connection().clientProtocols() != rpc::supports::kNone);
-        // Set the operation protocol
-        auto negotiatedProtocol =
-            rpc::negotiate(op->connection().serverProtocols(), op->connection().clientProtocols());
-
-        if (!negotiatedProtocol.isOK()) {
-            // Add relatively verbose logging here, since this should not happen unless we are
-            // mongos and we try to connect to a node that doesn't support OP_COMMAND.
-            warning() << "failed to negotiate protocol with remote host: " << op->request().target;
-            warning() << "request was: " << redact(op->request().cmdObj);
-            warning() << "response was: " << redact(commandReply.data);
-
-            auto clientProtos = rpc::toString(op->connection().clientProtocols());
-            if (clientProtos.isOK()) {
-                warning() << "our (client) supported protocols: " << clientProtos.getValue();
-            }
-            auto serverProtos = rpc::toString(op->connection().serverProtocols());
-            if (serverProtos.isOK()) {
-                warning() << "remote server's supported protocols:" << serverProtos.getValue();
-            }
-            return _completeOperation(op, negotiatedProtocol.getStatus());
-        }
-
-        op->setOperationProtocol(negotiatedProtocol.getValue());
-
-        op->connection().getCompressorManager().clientFinish(commandReply.data);
-
-        if (_hook) {
-            // Run the validation hook.
-            auto validHost = callNoexcept(
-                *_hook, &NetworkConnectionHook::validateHost, op->request().target, commandReply);
-            if (!validHost.isOK()) {
-                return _completeOperation(op, validHost);
-            }
-        }
-
-        return _authenticate(op);
-
-    };
-
-    _asyncRunCommand(op, [this, op, parseIsMaster](std::error_code ec, size_t bytes) {
-        _validateAndRun(op, ec, std::move(parseIsMaster));
-    });
-}
-
-void NetworkInterfaceASIO::_authenticate(AsyncOp* op) {
-    // There is currently no way for NetworkInterfaceASIO's users to run a command
-    // without going through _authenticate(). Callers may want to run certain commands,
-    // such as ismasters, pre-auth. We may want to offer this choice in the future.
-
-    // This check is sufficient to see if auth is enabled on the system,
-    // and avoids creating dependencies on deeper, less accessible auth code.
-    if (!isInternalAuthSet()) {
-        return _runConnectionHook(op);
-    }
-
-    // We will only have a valid clientName if SSL is enabled.
-    std::string clientName;
-#ifdef MONGO_CONFIG_SSL
-    if (getSSLManager()) {
-        clientName = getSSLManager()->getSSLConfiguration().clientSubjectName.toString();
-    }
-#endif
-
-    // authenticateClient will use this to run auth-related commands over our connection.
-    auto runCommandHook = [this, op](executor::RemoteCommandRequest request,
-                                     auth::AuthCompletionHandler handler) {
-
-        // SERVER-14170: Set the metadataHook to nullptr explicitly as we cannot write metadata
-        // here.
-        auto beginStatus = op->beginCommand(request);
-        if (!beginStatus.isOK()) {
-            return handler(beginStatus);
-        }
-
-        auto callAuthCompletionHandler = [this, op, handler]() {
-            auto authResponse = op->command().response(op, op->operationProtocol(), now(), nullptr);
-            handler(authResponse);
-        };
-
-        _asyncRunCommand(op,
-                         [this, op, callAuthCompletionHandler](std::error_code ec, size_t bytes) {
-                             _validateAndRun(op, ec, callAuthCompletionHandler);
-                         });
-    };
-
-    // This will be called when authentication has completed.
-    auto authHook = [this, op](auth::AuthResponse response) {
-        if (!response.isOK())
-            return _completeOperation(op, response);
-        return _runConnectionHook(op);
-    };
-
-    auto params = getInternalUserAuthParams();
-    auth::authenticateClient(params, op->request().target, clientName, runCommandHook, authHook);
-}
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/network_interface_asio_command.cpp b/src/mongo/executor/network_interface_asio_command.cpp
deleted file mode 100644
index ca111a09f51..00000000000
--- a/src/mongo/executor/network_interface_asio_command.cpp
+++ /dev/null
@@ -1,506 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/network_interface_asio.h"
-
-#include <type_traits>
-#include <utility>
-
-#include "mongo/base/static_assert.h"
-#include "mongo/db/dbmessage.h"
-#include "mongo/db/jsobj.h"
-#include "mongo/executor/async_stream_interface.h"
-#include "mongo/executor/connection_pool_asio.h"
-#include "mongo/rpc/factory.h"
-#include "mongo/rpc/metadata/metadata_hook.h"
-#include "mongo/rpc/protocol.h"
-#include "mongo/rpc/reply_interface.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/util/assert_util.h"
-#include "mongo/util/fail_point_service.h"
-#include "mongo/util/log.h"
-#include "mongo/util/mongoutils/str.h"
-
-namespace mongo {
-namespace executor {
-
-/**
- * The following send - receive utility functions are "stateless" in that they exist
- * apart from the AsyncOp state machine.
- */
-
-namespace {
-
-using namespace std::literals::string_literals;
-
-MONGO_FP_DECLARE(NetworkInterfaceASIOasyncRunCommandFail);
-
-using asio::ip::tcp;
-using ResponseStatus = TaskExecutor::ResponseStatus;
-
-// A type conforms to the NetworkHandler concept if it is a callable type that takes a
-// std::error_code and std::size_t and returns void. The std::error_code parameter is used
-// to inform the handler if the asynchronous operation it was waiting on succeeded, and the
-// size_t parameter conveys how many bytes were read or written.
-template <typename FunctionLike>
-using IsNetworkHandler =
-    std::is_convertible<FunctionLike, stdx::function<void(std::error_code, std::size_t)>>;
-
-template <typename Handler>
-void asyncSendMessage(AsyncStreamInterface& stream, Message* m, Handler&& handler) {
-    MONGO_STATIC_ASSERT_MSG(
-        IsNetworkHandler<Handler>::value,
-        "Handler passed to asyncSendMessage does not conform to NetworkHandler concept");
-    m->header().setResponseToMsgId(0);
-    m->header().setId(nextMessageId());
-    // TODO: Some day we may need to support vector messages.
-    fassert(28708, m->buf() != 0);
-    stream.write(asio::buffer(m->buf(), m->size()), std::forward<Handler>(handler));
-}
-
-template <typename Handler>
-void asyncRecvMessageHeader(AsyncStreamInterface& stream,
-                            MSGHEADER::Value* header,
-                            Handler&& handler) {
-    MONGO_STATIC_ASSERT_MSG(
-        IsNetworkHandler<Handler>::value,
-        "Handler passed to asyncRecvMessageHeader does not conform to NetworkHandler concept");
-    stream.read(asio::buffer(header->view().view2ptr(), sizeof(decltype(*header))),
-                std::forward<Handler>(handler));
-}
-
-template <typename Handler>
-void asyncRecvMessageBody(AsyncStreamInterface& stream,
-                          MSGHEADER::Value* header,
-                          Message* m,
-                          Handler&& handler) {
-    MONGO_STATIC_ASSERT_MSG(
-        IsNetworkHandler<Handler>::value,
-        "Handler passed to asyncRecvMessageBody does not conform to NetworkHandler concept");
-    // validate message length
-    int len = header->constView().getMessageLength();
-    if (len == 542393671) {
-        LOG(3) << "attempt to access MongoDB over HTTP on the native driver port.";
-        return handler(make_error_code(ErrorCodes::ProtocolError), 0);
-    } else if (static_cast<size_t>(len) < sizeof(MSGHEADER::Value) ||
-               static_cast<size_t>(len) > MaxMessageSizeBytes) {
-        warning() << "recv(): message len " << len << " is invalid. "
-                  << "Min " << sizeof(MSGHEADER::Value) << " Max: " << MaxMessageSizeBytes;
-        return handler(make_error_code(ErrorCodes::InvalidLength), 0);
-    }
-
-    int z = (len + 1023) & 0xfffffc00;
-    invariant(z >= len);
-    m->setData(SharedBuffer::allocate(z));
-    MsgData::View mdView = m->buf();
-
-    // copy header data into master buffer
-    int headerLen = sizeof(MSGHEADER::Value);
-    memcpy(mdView.view2ptr(), header, headerLen);
-    int bodyLength = len - headerLen;
-    invariant(bodyLength >= 0);
-
-    // receive remaining data into md->data
-    stream.read(asio::buffer(mdView.data(), bodyLength), std::forward<Handler>(handler));
-}
-
-ResponseStatus decodeRPC(Message* received,
-                         rpc::Protocol protocol,
-                         Milliseconds elapsed,
-                         const HostAndPort& source,
-                         rpc::EgressMetadataHook* metadataHook) {
-    try {
-        // makeReply will throw if the reply is invalid
-        auto reply = rpc::makeReply(received);
-        if (reply->getProtocol() != protocol) {
-            auto requestProtocol = rpc::toString(static_cast<rpc::ProtocolSet>(protocol));
-            if (!requestProtocol.isOK())
-                return {requestProtocol.getStatus(), elapsed};
-
-            return {ErrorCodes::RPCProtocolNegotiationFailed,
-                    str::stream() << "Mismatched RPC protocols - request was '"
-                                  << requestProtocol.getValue().toString()
-                                  << "' '"
-                                  << " but reply was '"
-                                  << networkOpToString(received->operation())
-                                  << "'",
-                    elapsed};
-        }
-        auto commandReply = reply->getCommandReply();
-        auto replyMetadata = reply->getMetadata();
-
-        // Handle incoming reply metadata.
-        if (metadataHook) {
-            auto listenStatus = callNoexcept(*metadataHook,
-                                             &rpc::EgressMetadataHook::readReplyMetadata,
-                                             nullptr,  // adding operationTime is handled via lambda
-                                             source.toString(),
-                                             replyMetadata);
-            if (!listenStatus.isOK()) {
-                return {listenStatus, elapsed};
-            }
-        }
-
-        return {RemoteCommandResponse(
-            std::move(*received), std::move(commandReply), std::move(replyMetadata), elapsed)};
-    } catch (...) {
-        return {exceptionToStatus(), elapsed};
-    }
-}
-
-}  // namespace
-
-NetworkInterfaceASIO::AsyncCommand::AsyncCommand(AsyncConnection* conn,
-                                                 Message&& command,
-                                                 Date_t now,
-                                                 const HostAndPort& target)
-    : _conn(conn), _toSend(std::move(command)), _start(now), _target(target) {
-    _toSend.header().setResponseToMsgId(0);
-}
-
-NetworkInterfaceASIO::AsyncConnection& NetworkInterfaceASIO::AsyncCommand::conn() {
-    return *_conn;
-}
-
-Message& NetworkInterfaceASIO::AsyncCommand::toSend() {
-    return _toSend;
-}
-
-Message& NetworkInterfaceASIO::AsyncCommand::toRecv() {
-    return _toRecv;
-}
-
-MSGHEADER::Value& NetworkInterfaceASIO::AsyncCommand::header() {
-    return _header;
-}
-
-ResponseStatus NetworkInterfaceASIO::AsyncCommand::response(AsyncOp* op,
-                                                            rpc::Protocol protocol,
-                                                            Date_t now,
-                                                            rpc::EgressMetadataHook* metadataHook) {
-    auto& received = _toRecv;
-    if (received.operation() == dbCompressed) {
-        auto swm = conn().getCompressorManager().decompressMessage(received);
-        if (!swm.isOK()) {
-            return swm.getStatus();
-        }
-        received = std::move(swm.getValue());
-    }
-
-    auto rs = decodeRPC(&received, protocol, now - _start, _target, metadataHook);
-    if (rs.isOK())
-        op->setResponseMetadata(rs.metadata);
-    return rs;
-}
-
-void NetworkInterfaceASIO::_startCommand(AsyncOp* op) {
-    LOG(3) << "running command " << redact(op->request().cmdObj) << " against database "
-           << op->request().dbname << " across network to " << op->request().target.toString();
-    if (inShutdown()) {
-        return;
-    }
-
-    // _connect() will continue the state machine.
-    _connect(op);
-}
-
-void NetworkInterfaceASIO::_beginCommunication(AsyncOp* op) {
-    // The way that we connect connections for the connection pool is by
-    // starting the callback chain with connect(), but getting off at the first
-    // _beginCommunication. I.e. all AsyncOp's start off with _inSetup == true
-    // and arrive here as they're connected and authed. Once they hit here, we
-    // return to the connection pool's get() callback with _inSetup == false,
-    // so we can proceed with user operations after they return to this
-    // codepath.
-    if (op->_inSetup) {
-        auto host = op->request().target;
-        auto getConnectionDuration = now() - op->start();
-        log() << "Successfully connected to " << host << ", took " << getConnectionDuration << " ("
-              << _connectionPool.getNumConnectionsPerHost(host) << " connections now open to "
-              << host << ")";
-        op->_inSetup = false;
-        op->finish(RemoteCommandResponse());
-        return;
-    }
-
-    LOG(3) << "Initiating asynchronous command: " << redact(op->request().toString());
-
-    auto beginStatus = op->beginCommand(op->request());
-    if (!beginStatus.isOK()) {
-        return _completeOperation(op, beginStatus);
-    }
-
-    _asyncRunCommand(op, [this, op](std::error_code ec, size_t bytes) {
-        _validateAndRun(op, ec, [this, op]() { _completedOpCallback(op); });
-    });
-}
-
-void NetworkInterfaceASIO::_completedOpCallback(AsyncOp* op) {
-    auto response = op->command().response(op, op->operationProtocol(), now(), _metadataHook.get());
-    _completeOperation(op, response);
-}
-
-void NetworkInterfaceASIO::_networkErrorCallback(AsyncOp* op, const std::error_code& ec) {
-    ErrorCodes::Error errorCode = (ec.category() == mongoErrorCategory())
-        ? ErrorCodes::Error(ec.value())
-        : ErrorCodes::HostUnreachable;
-    _completeOperation(op, {errorCode, ec.message(), Milliseconds(now() - op->_start)});
-}
-
-// NOTE: This method may only be called by ASIO threads
-// (do not call from methods entered by TaskExecutor threads)
-void NetworkInterfaceASIO::_completeOperation(AsyncOp* op, ResponseStatus resp) {
-    auto metadata = op->getResponseMetadata();
-    if (!metadata.isEmpty()) {
-        resp.metadata = metadata;
-    }
-
-    // Cancel this operation's timeout. Note that the timeout callback may already be running,
-    // may have run, or may have already been scheduled to run in the near future.
-    if (op->_timeoutAlarm) {
-        op->_timeoutAlarm->cancel();
-    }
-
-    if (ErrorCodes::isExceededTimeLimitError(resp.status.code())) {
-        _numTimedOutOps.fetchAndAdd(1);
-    }
-
-    if (op->_inSetup) {
-        // If we are in setup we should only be here if we failed to connect.
-        MONGO_ASIO_INVARIANT(!resp.isOK(), "Failed to connect in setup", op);
-        // If we fail during connection, we won't be able to access any of op's members after
-        // calling finish(), so we return here.
-        log() << "Failed to connect to " << op->request().target << " - " << redact(resp.status);
-        op->finish(std::move(resp));
-        return;
-    }
-
-    if (op->_inRefresh) {
-        // If we are in refresh we should only be here if we failed to heartbeat.
-        MONGO_ASIO_INVARIANT(!resp.isOK(), "In refresh, but did not fail to heartbeat", op);
-        // If we fail during heartbeating, we won't be able to access any of op's members after
-        // calling finish(), so we return here.
-        log() << "Failed asio heartbeat to "
-              << (op->commandIsInitialized() ? op->command().target().toString() : "unknown"s)
-              << " - " << redact(resp.status);
-        _numFailedOps.fetchAndAdd(1);
-        op->finish(std::move(resp));
-        return;
-    }
-
-    if (!resp.isOK()) {
-        // In the case that resp is not OK, but _inSetup is false, we are using a connection
-        // that we got from the pool to execute a command, but it failed for some reason.
-        if (op->commandIsInitialized() && shouldLog(LogstreamBuilder::severityCast(2))) {
-            const auto performLog = [&resp](Message& message) {
-                LOG(2) << "Failed to send message. Reason: " << redact(resp.status) << ". Message: "
-                       << rpc::opMsgRequestFromAnyProtocol(message).body.toString(
-                              logger::globalLogDomain()->shouldRedactLogs());
-            };
-
-            // Message might be compressed, decompress in that case so we can log the body
-            Message& maybeCompressed = op->command().toSend();
-            if (maybeCompressed.operation() != dbCompressed) {
-                performLog(maybeCompressed);
-            } else {
-                StatusWith<Message> decompressedMessage =
-                    op->command().conn().getCompressorManager().decompressMessage(maybeCompressed);
-                if (decompressedMessage.isOK()) {
-                    performLog(decompressedMessage.getValue());
-                } else {
-                    LOG(2) << "Failed to execute a command.  Reason: " << redact(resp.status)
-                           << ". Decompression failed with: "
-                           << redact(decompressedMessage.getStatus());
-                }
-            }
-        } else {
-            LOG(2) << "Failed to execute a command.  Reason: " << redact(resp.status);
-        }
-
-        if (resp.status.code() != ErrorCodes::CallbackCanceled) {
-            _numFailedOps.fetchAndAdd(1);
-        }
-    } else {
-        _numSucceededOps.fetchAndAdd(1);
-    }
-
-    std::unique_ptr<AsyncOp> ownedOp;
-
-    {
-        stdx::lock_guard<stdx::mutex> lk(_inProgressMutex);
-
-        auto iter = _inProgress.find(op);
-
-        MONGO_ASIO_INVARIANT_INLOCK(
-            iter != _inProgress.end(), "Could not find AsyncOp in _inProgress", op);
-
-        ownedOp = std::move(iter->second);
-        _inProgress.erase(iter);
-    }
-
-    op->finish(std::move(resp));
-
-    MONGO_ASIO_INVARIANT(static_cast<bool>(ownedOp), "Invalid AsyncOp", op);
-
-    auto conn = std::move(op->_connectionPoolHandle);
-    auto asioConn = static_cast<connection_pool_asio::ASIOConnection*>(conn.get());
-
-    // Prevent any other threads or callbacks from accessing this op so we may safely complete
-    // and destroy it. It is key that we do this after we remove the op from the _inProgress map
-    // or someone else in cancelCommand could read the bumped generation and cancel the next
-    // command that uses this op. See SERVER-20556.
-    {
-        stdx::lock_guard<stdx::mutex> lk(op->_access->mutex);
-        ++(op->_access->id);
-    }
-
-    // We need to bump the generation BEFORE we call reset() or we could flip the timeout in the
-    // timeout callback before returning the AsyncOp to the pool.
-    ownedOp->reset();
-
-    asioConn->bindAsyncOp(std::move(ownedOp));
-    if (!resp.isOK()) {
-        asioConn->indicateFailure(resp.status);
-    } else {
-        asioConn->indicateUsed();
-        asioConn->indicateSuccess();
-    }
-
-    signalWorkAvailable();
-}
-
-void NetworkInterfaceASIO::_asyncRunCommand(AsyncOp* op, NetworkOpHandler handler) {
-    LOG(2) << "Starting asynchronous command " << op->request().id << " on host "
-           << op->request().target.toString();
-
-    if (MONGO_FAIL_POINT(NetworkInterfaceASIOasyncRunCommandFail)) {
-        _validateAndRun(op, asio::error::basic_errors::network_unreachable, [] {});
-        return;
-    }
-
-    // We invert the following steps below to run a command:
-    // 1 - send the given command
-    // 2 - receive a header for the response
-    // 3 - validate and receive response body
-    // 4 - advance the state machine by calling handler()
-    auto& cmd = op->command();
-
-    // Step 4
-    auto recvMessageCallback = [handler](std::error_code ec, size_t bytes) {
-        // We don't call _validateAndRun here as we assume the caller will.
-        handler(ec, bytes);
-    };
-
-    // Step 3
-    auto recvHeaderCallback = [this, &cmd, handler, recvMessageCallback, op](std::error_code ec,
-                                                                             size_t bytes) {
-        // The operation could have been canceled after starting the command, but before
-        // receiving the header
-        _validateAndRun(op, ec, [recvMessageCallback, bytes, &cmd, handler] {
-            // validate response id
-            uint32_t expectedId = cmd.toSend().header().getId();
-            uint32_t actualId = cmd.header().constView().getResponseToMsgId();
-            if (actualId != expectedId) {
-                LOG(3) << "got wrong response:"
-                       << " expected response id: " << expectedId
-                       << ", got response id: " << actualId;
-                return handler(make_error_code(ErrorCodes::ProtocolError), bytes);
-            }
-
-            asyncRecvMessageBody(
-                cmd.conn().stream(), &cmd.header(), &cmd.toRecv(), std::move(recvMessageCallback));
-        });
-    };
-
-    // Step 2
-    auto sendMessageCallback = [this, &cmd, handler, recvHeaderCallback, op](std::error_code ec,
-                                                                             size_t bytes) {
-        _validateAndRun(op, ec, [&cmd, recvHeaderCallback] {
-            asyncRecvMessageHeader(
-                cmd.conn().stream(), &cmd.header(), std::move(recvHeaderCallback));
-        });
-
-
-    };
-
-    // Step 1
-    asyncSendMessage(cmd.conn().stream(), &cmd.toSend(), std::move(sendMessageCallback));
-}
-
-void NetworkInterfaceASIO::_runConnectionHook(AsyncOp* op) {
-    if (!_hook) {
-        return _beginCommunication(op);
-    }
-
-    auto swOptionalRequest =
-        callNoexcept(*_hook, &NetworkConnectionHook::makeRequest, op->request().target);
-
-    if (!swOptionalRequest.isOK()) {
-        return _completeOperation(op, swOptionalRequest.getStatus());
-    }
-
-    auto optionalRequest = std::move(swOptionalRequest.getValue());
-
-    if (optionalRequest == boost::none) {
-        return _beginCommunication(op);
-    }
-
-    auto beginStatus = op->beginCommand(*optionalRequest);
-    if (!beginStatus.isOK()) {
-        return _completeOperation(op, beginStatus);
-    }
-
-    auto finishHook = [this, op]() {
-        auto response =
-            op->command().response(op, op->operationProtocol(), now(), _metadataHook.get());
-
-        if (!response.isOK()) {
-            return _completeOperation(op, response);
-        }
-
-        auto handleStatus = callNoexcept(
-            *_hook, &NetworkConnectionHook::handleReply, op->request().target, std::move(response));
-
-        if (!handleStatus.isOK()) {
-            return _completeOperation(op, handleStatus);
-        }
-
-        return _beginCommunication(op);
-    };
-
-    return _asyncRunCommand(op, [this, op, finishHook](std::error_code ec, std::size_t bytes) {
-        _validateAndRun(op, ec, finishHook);
-    });
-}
-
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/network_interface_asio_connect.cpp b/src/mongo/executor/network_interface_asio_connect.cpp
deleted file mode 100644
index 57a9f302b58..00000000000
--- a/src/mongo/executor/network_interface_asio_connect.cpp
+++ /dev/null
@@ -1,110 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/network_interface_asio.h"
-
-#include <utility>
-
-#include "mongo/base/system_error.h"
-#include "mongo/config.h"
-#include "mongo/db/wire_version.h"
-#include "mongo/executor/async_stream.h"
-#include "mongo/executor/async_stream_factory.h"
-#include "mongo/executor/async_stream_interface.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/util/log.h"
-
-namespace mongo {
-namespace executor {
-
-using asio::ip::tcp;
-
-NetworkInterfaceASIO::AsyncConnection::AsyncConnection(std::unique_ptr<AsyncStreamInterface> stream,
-                                                       rpc::ProtocolSet protocols)
-    : _stream(std::move(stream)),
-      _serverProtocols(protocols),
-      _clientProtocols(rpc::computeProtocolSet(WireSpec::instance().outgoing)) {}
-
-AsyncStreamInterface& NetworkInterfaceASIO::AsyncConnection::stream() {
-    return *_stream;
-}
-
-void NetworkInterfaceASIO::AsyncConnection::cancel() {
-    _stream->cancel();
-}
-
-rpc::ProtocolSet NetworkInterfaceASIO::AsyncConnection::serverProtocols() const {
-    return _serverProtocols;
-}
-
-rpc::ProtocolSet NetworkInterfaceASIO::AsyncConnection::clientProtocols() const {
-    return _clientProtocols;
-}
-
-void NetworkInterfaceASIO::AsyncConnection::setServerProtocols(rpc::ProtocolSet protocols) {
-    _serverProtocols = protocols;
-}
-
-void NetworkInterfaceASIO::_connect(AsyncOp* op) {
-    log() << "Connecting to " << op->request().target.toString();
-
-    tcp::resolver::query query(op->request().target.host(),
-                               std::to_string(op->request().target.port()));
-    // TODO: Investigate how we might hint or use shortcuts to resolve when possible.
-    const auto thenConnect = [this, op](std::error_code ec, tcp::resolver::iterator endpoints) {
-        if (endpoints == tcp::resolver::iterator()) {
-            // Workaround a bug in ASIO returning an invalid resolver iterator (with a non-error
-            // std::error_code) when file descriptors are exhausted.
-            ec = make_error_code(ErrorCodes::HostUnreachable);
-        }
-        _validateAndRun(
-            op, ec, [this, op, endpoints]() { _setupSocket(op, std::move(endpoints)); });
-    };
-    op->resolver().async_resolve(query, op->_strand.wrap(std::move(thenConnect)));
-}
-
-void NetworkInterfaceASIO::_setupSocket(AsyncOp* op, tcp::resolver::iterator endpoints) {
-    // TODO: Consider moving this call to post-auth so we only assign completed connections.
-    {
-        auto stream = _streamFactory->makeStream(&op->strand(), op->request().target);
-        op->setConnection({std::move(stream), rpc::supports::kOpQueryOnly});
-    }
-
-    auto& stream = op->connection().stream();
-
-    stream.connect(std::move(endpoints), [this, op](std::error_code ec) {
-        _validateAndRun(op, ec, [this, op]() { _runIsMaster(op); });
-    });
-}
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/network_interface_asio_integration_test.cpp b/src/mongo/executor/network_interface_asio_integration_test.cpp
deleted file mode 100644
index 79688a60d19..00000000000
--- a/src/mongo/executor/network_interface_asio_integration_test.cpp
+++ /dev/null
@@ -1,236 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include <algorithm>
-#include <exception>
-
-#include "mongo/client/connection_string.h"
-#include "mongo/executor/network_interface_asio_integration_fixture.h"
-#include "mongo/executor/network_interface_asio_test_utils.h"
-#include "mongo/platform/random.h"
-#include "mongo/rpc/get_status_from_command_result.h"
-#include "mongo/stdx/future.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/unittest/integration_test.h"
-#include "mongo/unittest/unittest.h"
-#include "mongo/util/assert_util.h"
-#include "mongo/util/concurrency/thread_pool.h"
-#include "mongo/util/log.h"
-#include "mongo/util/scopeguard.h"
-
-namespace mongo {
-namespace executor {
-namespace {
-
-TEST_F(NetworkInterfaceASIOIntegrationFixture, Ping) {
-    startNet();
-    assertCommandOK("admin", BSON("ping" << 1));
-}
-
-TEST_F(NetworkInterfaceASIOIntegrationFixture, Timeouts) {
-    startNet();
-    // This sleep command will take 10 seconds, so we should time out client side first given
-    // our timeout of 100 milliseconds.
-    assertCommandFailsOnClient("admin",
-                               BSON("sleep" << 1 << "lock"
-                                            << "none"
-                                            << "secs"
-                                            << 10),
-                               ErrorCodes::NetworkInterfaceExceededTimeLimit,
-                               Milliseconds(100));
-
-    // Run a sleep command that should return before we hit the ASIO timeout.
-    assertCommandOK("admin",
-                    BSON("sleep" << 1 << "lock"
-                                 << "none"
-                                 << "secs"
-                                 << 1),
-                    Milliseconds(10000000));
-}
-
-class StressTestOp {
-public:
-    using Fixture = NetworkInterfaceASIOIntegrationFixture;
-    using Pool = ThreadPoolInterface;
-
-    void run(Fixture* fixture,
-             StartCommandCB onFinish,
-             Milliseconds timeout = RemoteCommandRequest::kNoTimeout) {
-        auto cb = makeCallbackHandle();
-
-        RemoteCommandRequest request{unittest::getFixtureConnectionString().getServers()[0],
-                                     "admin",
-                                     _command,
-                                     nullptr,
-                                     timeout};
-
-        fixture->startCommand(cb, request, onFinish);
-
-        if (_cancel) {
-            invariant(fixture->getRandomNumberGenerator());
-            sleepmillis(fixture->getRandomNumberGenerator()->nextInt32(10));
-            fixture->net().cancelCommand(cb);
-        }
-    }
-
-    static void runTimeoutOp(Fixture* fixture, StartCommandCB onFinish) {
-        return StressTestOp(BSON("sleep" << 1 << "lock"
-                                         << "none"
-                                         << "secs"
-                                         << 1),
-                            false)
-            .run(fixture, onFinish, Milliseconds(100));
-    }
-
-    static void runCompleteOp(Fixture* fixture, StartCommandCB onFinish) {
-        return StressTestOp(BSON("sleep" << 1 << "lock"
-                                         << "none"
-                                         << "millis"
-                                         << 100),
-                            false)
-            .run(fixture, onFinish);
-    }
-
-    static void runCancelOp(Fixture* fixture, StartCommandCB onFinish) {
-        return StressTestOp(BSON("sleep" << 1 << "lock"
-                                         << "none"
-                                         << "secs"
-                                         << 10),
-                            true)
-            .run(fixture, onFinish);
-    }
-
-    static void runLongOp(Fixture* fixture, StartCommandCB onFinish) {
-        return StressTestOp(BSON("sleep" << 1 << "lock"
-                                         << "none"
-                                         << "secs"
-                                         << 30),
-                            false)
-            .run(fixture, onFinish);
-    }
-
-private:
-    StressTestOp(const BSONObj& command, bool cancel) : _command(command), _cancel(cancel) {}
-
-    BSONObj _command;
-    bool _cancel;
-};
-
-TEST_F(NetworkInterfaceASIOIntegrationFixture, StressTest) {
-    constexpr std::size_t numOps = 500;
-    RemoteCommandResponse testResults[numOps];
-    ErrorCodes::Error expectedResults[numOps];
-    CountdownLatch cl(numOps);
-
-    startNet();
-
-    std::unique_ptr<SecureRandom> seedSource{SecureRandom::create()};
-    auto seed = seedSource->nextInt64();
-
-    log() << "Random seed is " << seed;
-    auto rng = PseudoRandom(seed);  // TODO: read from command line
-    setRandomNumberGenerator(&rng);
-    log() << "Starting stress test...";
-
-    for (std::size_t i = 0; i < numOps; ++i) {
-        // stagger operations slightly to mitigate connection pool contention
-        sleepmillis(rng.nextInt32(50));
-
-        auto r = rng.nextCanonicalDouble();
-
-        auto cb = [&testResults, &cl, i](const RemoteCommandResponse& resp) {
-            testResults[i] = resp;
-            cl.countDown();
-        };
-
-        if (r < .3) {
-            expectedResults[i] = ErrorCodes::CallbackCanceled;
-            StressTestOp::runCancelOp(this, cb);
-        } else if (r < .7) {
-            expectedResults[i] = ErrorCodes::OK;
-            StressTestOp::runCompleteOp(this, cb);
-        } else if (r < .99) {
-            expectedResults[i] = ErrorCodes::NetworkInterfaceExceededTimeLimit;
-            StressTestOp::runTimeoutOp(this, cb);
-        } else {
-            // Just a sprinkling of long ops, to mitigate connection pool contention
-            expectedResults[i] = ErrorCodes::OK;
-            StressTestOp::runLongOp(this, cb);
-        }
-    };
-
-    cl.await();
-
-    for (std::size_t i = 0; i < numOps; ++i) {
-        const auto& resp = testResults[i];
-        auto ec = resp.isOK() ? getStatusFromCommandResult(resp.data) : resp.status;
-        ASSERT_EQ(ec, expectedResults[i]);
-    }
-}
-
-// Hook that intentionally never finishes
-class HangingHook : public executor::NetworkConnectionHook {
-    Status validateHost(const HostAndPort&, const RemoteCommandResponse&) final {
-        return Status::OK();
-    }
-
-    StatusWith<boost::optional<RemoteCommandRequest>> makeRequest(
-        const HostAndPort& remoteHost) final {
-        return {boost::make_optional(RemoteCommandRequest(remoteHost,
-                                                          "admin",
-                                                          BSON("sleep" << 1 << "lock"
-                                                                       << "none"
-                                                                       << "secs"
-                                                                       << 100000000),
-                                                          BSONObj(),
-                                                          nullptr))};
-    }
-
-    Status handleReply(const HostAndPort& remoteHost, RemoteCommandResponse&& response) final {
-        MONGO_UNREACHABLE;
-    }
-};
-
-
-// Test that we time out a command if the connection hook hangs.
-TEST_F(NetworkInterfaceASIOIntegrationFixture, HookHangs) {
-    NetworkInterfaceASIO::Options options;
-    options.networkConnectionHook = stdx::make_unique<HangingHook>();
-    startNet(std::move(options));
-
-    assertCommandFailsOnClient(
-        "admin", BSON("ping" << 1), ErrorCodes::NetworkInterfaceExceededTimeLimit, Seconds(1));
-}
-
-}  // namespace
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/network_interface_asio_operation.cpp b/src/mongo/executor/network_interface_asio_operation.cpp
deleted file mode 100644
index 4a78f0c076e..00000000000
--- a/src/mongo/executor/network_interface_asio_operation.cpp
+++ /dev/null
@@ -1,408 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/executor/network_interface_asio.h"
-
-#include "mongo/base/status_with.h"
-#include "mongo/db/query/getmore_request.h"
-#include "mongo/db/query/query_request.h"
-#include "mongo/executor/async_stream_interface.h"
-#include "mongo/executor/connection_pool_asio.h"
-#include "mongo/executor/network_interface_asio.h"
-#include "mongo/rpc/factory.h"
-#include "mongo/rpc/metadata/metadata_hook.h"
-#include "mongo/util/log.h"
-#include "mongo/util/time_support.h"
-
-#define MONGO_ASYNC_OP_INVARIANT(_Expression, _Error)  \
-    do {                                               \
-        if (MONGO_unlikely(!(_Expression))) {          \
-            _failWithInfo(__FILE__, __LINE__, _Error); \
-        }                                              \
-    } while (false)
-
-namespace mongo {
-namespace executor {
-
-using asio::ip::tcp;
-
-namespace {
-
-// Used to generate unique identifiers for AsyncOps, the same AsyncOp may
-// be used to run multiple distinct requests.
-AtomicUInt64 kAsyncOpIdCounter(0);
-
-}  // namespace
-
-const NetworkInterfaceASIO::TableRow NetworkInterfaceASIO::AsyncOp::kFieldLabels = {
-    "", "id", "states", "start_time", "request"};
-
-NetworkInterfaceASIO::AsyncOp::AsyncOp(NetworkInterfaceASIO* const owner,
-                                       const TaskExecutor::CallbackHandle& cbHandle,
-                                       const RemoteCommandRequest& request,
-                                       const RemoteCommandCompletionFn& onFinish,
-                                       Date_t now)
-    : _owner(owner),
-      _cbHandle(cbHandle),
-      _request(request),
-      _onFinish(onFinish),
-      _start(now),
-      _resolver(owner->_io_service),
-      _id(kAsyncOpIdCounter.addAndFetch(1)),
-      _access(std::make_shared<AsyncOp::AccessControl>()),
-      _inSetup(true),
-      _inRefresh(false),
-      _strand(owner->_io_service) {
-    // No need to take lock when we aren't yet constructed.
-    _transitionToState_inlock(State::kUninitialized);
-}
-
-void NetworkInterfaceASIO::AsyncOp::cancel() {
-    LOG(2) << "Canceling operation; original request was: " << redact(request().toString());
-    stdx::lock_guard<stdx::mutex> lk(_access->mutex);
-    auto access = _access;
-    auto generation = access->id;
-
-    // An operation may be in mid-flight when it is canceled, so we cancel any
-    // in-progress async ops but do not complete the operation now.
-
-    _strand.post([this, access, generation] {
-        stdx::lock_guard<stdx::mutex> lk(access->mutex);
-        if (generation == access->id) {
-            _transitionToState_inlock(AsyncOp::State::kCanceled);
-            if (_connection) {
-                _connection->cancel();
-            }
-        }
-    });
-}
-
-bool NetworkInterfaceASIO::AsyncOp::canceled() const {
-    return _hasSeenState(State::kCanceled);
-}
-
-void NetworkInterfaceASIO::AsyncOp::timeOut_inlock() {
-    LOG(2) << "Operation timing out; original request was: " << redact(request().toString());
-    auto access = _access;
-    auto generation = access->id;
-
-    // An operation may be in mid-flight when it times out, so we cancel any
-    // in-progress stream operations but do not complete the operation now.
-
-    _strand.post([this, access, generation] {
-        stdx::lock_guard<stdx::mutex> lk(access->mutex);
-        if (generation == access->id) {
-            _transitionToState_inlock(AsyncOp::State::kTimedOut);
-            if (_connection) {
-                _connection->cancel();
-            }
-        }
-    });
-}
-
-bool NetworkInterfaceASIO::AsyncOp::timedOut() const {
-    return _hasSeenState(State::kTimedOut);
-}
-
-const TaskExecutor::CallbackHandle& NetworkInterfaceASIO::AsyncOp::cbHandle() const {
-    return _cbHandle;
-}
-
-NetworkInterfaceASIO::AsyncConnection& NetworkInterfaceASIO::AsyncOp::connection() {
-    MONGO_ASYNC_OP_INVARIANT(_connection.is_initialized(), "Connection not yet initialized");
-    return *_connection;
-}
-
-void NetworkInterfaceASIO::AsyncOp::setConnection(AsyncConnection&& conn) {
-    MONGO_ASYNC_OP_INVARIANT(!_connection.is_initialized(), "Connection already initialized");
-    _connection = std::move(conn);
-}
-
-Status NetworkInterfaceASIO::AsyncOp::beginCommand(Message&& newCommand,
-                                                   const HostAndPort& target) {
-    // NOTE: We operate based on the assumption that AsyncOp's
-    // AsyncConnection does not change over its lifetime.
-    MONGO_ASYNC_OP_INVARIANT(_connection.is_initialized(),
-                             "Connection should not change over AsyncOp's lifetime");
-
-    auto swm = _connection->getCompressorManager().compressMessage(newCommand);
-    if (!swm.isOK())
-        return swm.getStatus();
-
-    // Construct a new AsyncCommand object for each command.
-    _command.emplace(_connection.get_ptr(), std::move(swm.getValue()), _owner->now(), target);
-    return Status::OK();
-}
-
-Status NetworkInterfaceASIO::AsyncOp::beginCommand(const RemoteCommandRequest& request) {
-    return beginCommand(
-        rpc::messageFromOpMsgRequest(
-            operationProtocol(),
-            OpMsgRequest::fromDBAndBody(request.dbname, request.cmdObj, request.metadata)),
-        request.target);
-}
-
-NetworkInterfaceASIO::AsyncCommand& NetworkInterfaceASIO::AsyncOp::command() {
-    MONGO_ASYNC_OP_INVARIANT(_command.is_initialized(), "Command is not yet initialized");
-
-    return *_command;
-}
-
-bool NetworkInterfaceASIO::AsyncOp::commandIsInitialized() const {
-    return _command.is_initialized();
-}
-
-void NetworkInterfaceASIO::AsyncOp::finish(ResponseStatus&& rs) {
-    // We never hold the access lock when we call finish from NetworkInterfaceASIO.
-    _transitionToState(AsyncOp::State::kFinished);
-
-    LOG(2) << "Request " << _request.id << " finished with response: "
-           << redact(rs.isOK() ? rs.data.toString() : rs.status.toString());
-
-    // Calling the completion handler may invalidate state in this op, so do it last.
-    _onFinish(rs);
-}
-
-const RemoteCommandRequest& NetworkInterfaceASIO::AsyncOp::request() const {
-    return _request;
-}
-
-void NetworkInterfaceASIO::AsyncOp::startProgress(Date_t startTime) {
-    _start = startTime;
-    // We never hold the access lock when we call startProgress from NetworkInterfaceASIO.
-    _transitionToState(AsyncOp::State::kInProgress);
-}
-
-Date_t NetworkInterfaceASIO::AsyncOp::start() const {
-    return _start;
-}
-
-rpc::Protocol NetworkInterfaceASIO::AsyncOp::operationProtocol() const {
-    MONGO_ASYNC_OP_INVARIANT(_operationProtocol.is_initialized(), "Protocol not yet set");
-    return *_operationProtocol;
-}
-
-void NetworkInterfaceASIO::AsyncOp::setOperationProtocol(rpc::Protocol proto) {
-    MONGO_ASYNC_OP_INVARIANT(!_operationProtocol.is_initialized(), "Protocol already set");
-    _operationProtocol = proto;
-}
-
-void NetworkInterfaceASIO::AsyncOp::setResponseMetadata(BSONObj m) {
-    _responseMetadata = m;
-}
-
-BSONObj NetworkInterfaceASIO::AsyncOp::getResponseMetadata() {
-    return _responseMetadata;
-}
-
-void NetworkInterfaceASIO::AsyncOp::reset() {
-    // We don't reset owner as it never changes
-    _cbHandle = {};
-    _request = {};
-    _onFinish = {};
-    _connectionPoolHandle = {};
-    // We don't reset _connection as we want to reuse it.
-    // Ditto for _operationProtocol.
-    _start = {};
-    _timeoutAlarm.reset();
-    // _id stays the same for the lifetime of this object.
-    _command = boost::none;
-    // _inSetup should always be false at this point.
-    // We never hold the access lock when we call this from NetworkInterfaceASIO.
-    clearStateTransitions();
-}
-
-void NetworkInterfaceASIO::AsyncOp::clearStateTransitions() {
-    _transitionToState(AsyncOp::State::kUninitialized);
-}
-
-void NetworkInterfaceASIO::AsyncOp::setOnFinish(RemoteCommandCompletionFn&& onFinish) {
-    _onFinish = std::move(onFinish);
-}
-
-// Return a string representation of the given state.
-std::string NetworkInterfaceASIO::AsyncOp::_stateToString(AsyncOp::State state) const {
-    switch (state) {
-        case State::kUninitialized:
-            return "UNINITIALIZED";
-        case State::kInProgress:
-            return "IN_PROGRESS";
-        case State::kTimedOut:
-            return "TIMED_OUT";
-        case State::kCanceled:
-            return "CANCELED";
-        case State::kFinished:
-            return "DONE";
-        case State::kNoState:
-            return "---";
-        default:
-            MONGO_UNREACHABLE;
-    }
-}
-
-std::string NetworkInterfaceASIO::AsyncOp::_stateString() const {
-    str::stream s;
-    s << "[ ";
-
-    for (int i = 0; i < kMaxStateTransitions; i++) {
-        if (_states[i] == State::kNoState) {
-            break;
-        }
-
-        if (i != 0) {
-            s << ", ";
-        }
-
-        s << _stateToString(_states[i]);
-    }
-
-    s << " ]";
-
-    return s;
-}
-
-NetworkInterfaceASIO::TableRow NetworkInterfaceASIO::AsyncOp::getStringFields() const {
-    // We leave a placeholder for an asterisk
-    return {"", std::to_string(_id), _stateString(), _start.toString(), _request.toString()};
-}
-
-std::string NetworkInterfaceASIO::AsyncOp::toString() const {
-    str::stream s;
-    int fieldIdx = 1;
-    bool first = true;
-
-    for (auto field : getStringFields()) {
-        if (field != "") {
-            if (first) {
-                first = false;
-            } else {
-                s << ", ";
-            }
-
-            s << kFieldLabels[fieldIdx] << ": " << field;
-            fieldIdx++;
-        }
-    }
-    return s;
-}
-
-bool NetworkInterfaceASIO::AsyncOp::operator==(const AsyncOp& other) const {
-    return _id == other._id;
-}
-
-bool NetworkInterfaceASIO::AsyncOp::_hasSeenState(AsyncOp::State state) const {
-    return std::any_of(std::begin(_states), std::end(_states), [state](AsyncOp::State _state) {
-        return _state == state;
-    });
-}
-
-void NetworkInterfaceASIO::AsyncOp::_transitionToState(AsyncOp::State newState) {
-    stdx::lock_guard<stdx::mutex> lk(_access->mutex);
-    _transitionToState_inlock(newState);
-}
-
-void NetworkInterfaceASIO::AsyncOp::_transitionToState_inlock(AsyncOp::State newState) {
-    if (newState == State::kUninitialized) {
-        _states[0] = State::kUninitialized;
-        for (int i = 1; i < kMaxStateTransitions; i++) {
-            _states[i] = State::kNoState;
-        }
-        return;
-    }
-
-    // We can transition to cancelled multiple times if cancel() is called
-    // multiple times.  Ignore that transition if we're already cancelled.
-    if (newState == State::kCanceled) {
-        // Find the current state
-        auto iter = std::find_if_not(_states.rbegin(), _states.rend(), [](const State& state) {
-            return state == State::kNoState;
-        });
-
-        // If its cancelled, just return
-        if (iter != _states.rend() && *iter == State::kCanceled) {
-            return;
-        }
-    }
-
-    for (int i = 0; i < kMaxStateTransitions; i++) {
-        // We can't transition to the same state twice.
-        MONGO_ASYNC_OP_INVARIANT(_states[i] != newState,
-                                 "Cannot use the same state (" + _stateToString(newState) +
-                                     ") twice");
-
-        if (_states[i] == State::kNoState) {
-            // Perform some validation before transitioning.
-            switch (newState) {
-                case State::kInProgress:
-                    MONGO_ASYNC_OP_INVARIANT(i == 1,
-                                             "kInProgress must come directly after kUninitialized");
-                    break;
-                case State::kTimedOut:
-                    // During connection setup, it is possible to timeout before the stream is
-                    // initialized, so we have to allow this transition.
-                    break;
-                case State::kCanceled:
-                    MONGO_ASYNC_OP_INVARIANT(
-                        i > 1, _stateToString(newState) + " must come after kInProgress");
-                    MONGO_ASYNC_OP_INVARIANT(_states[i - 1] != State::kUninitialized,
-                                             _stateToString(newState) +
-                                                 " cannot come after kUninitialized");
-                    break;
-                case State::kFinished:
-                    MONGO_ASYNC_OP_INVARIANT(i > 0, "kFinished must come after kUninitialized");
-                    break;
-                default:
-                    MONGO_UNREACHABLE;
-            }
-
-            // Update state.
-            _states[i] = newState;
-            return;
-        }
-    }
-
-    // If we get here, we've already transitioned to the max allowed states, explode.
-    MONGO_UNREACHABLE;
-}
-
-void NetworkInterfaceASIO::AsyncOp::_failWithInfo(const char* file,
-                                                  int line,
-                                                  std::string error) const {
-    std::stringstream ss;
-    ss << "Invariant failure at " << file << ":" << line << ": " << error
-       << ", Operation: " << toString();
-    Status status{ErrorCodes::InternalError, ss.str()};
-    fassertFailedWithStatus(34430, status);
-}
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/network_interface_asio_test.cpp b/src/mongo/executor/network_interface_asio_test.cpp
deleted file mode 100644
index a5ca74a89c7..00000000000
--- a/src/mongo/executor/network_interface_asio_test.cpp
+++ /dev/null
@@ -1,1079 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kASIO
-
-#include "mongo/platform/basic.h"
-
-#include <boost/optional.hpp>
-
-#include "mongo/base/status_with.h"
-#include "mongo/db/jsobj.h"
-#include "mongo/db/wire_version.h"
-#include "mongo/executor/async_mock_stream_factory.h"
-#include "mongo/executor/async_timer_mock.h"
-#include "mongo/executor/network_interface_asio.h"
-#include "mongo/executor/network_interface_asio_test_utils.h"
-#include "mongo/executor/test_network_connection_hook.h"
-#include "mongo/rpc/factory.h"
-#include "mongo/rpc/legacy_reply_builder.h"
-#include "mongo/rpc/message.h"
-#include "mongo/rpc/metadata/egress_metadata_hook_list.h"
-#include "mongo/stdx/memory.h"
-#include "mongo/unittest/unittest.h"
-#include "mongo/util/log.h"
-#include "mongo/util/scopeguard.h"
-
-namespace mongo {
-namespace executor {
-namespace {
-
-using ResponseStatus = TaskExecutor::ResponseStatus;
-
-HostAndPort testHost{"localhost", 20000};
-
-void initWireSpecMongoD() {
-    WireSpec& spec = WireSpec::instance();
-    // accept from latest internal version
-    spec.incomingInternalClient.minWireVersion = LATEST_WIRE_VERSION;
-    spec.incomingInternalClient.maxWireVersion = LATEST_WIRE_VERSION;
-    // accept from any external version
-    spec.incomingExternalClient.minWireVersion = RELEASE_2_4_AND_BEFORE;
-    spec.incomingExternalClient.maxWireVersion = LATEST_WIRE_VERSION;
-    // connect to latest
-    spec.outgoing.minWireVersion = LATEST_WIRE_VERSION;
-    spec.outgoing.maxWireVersion = LATEST_WIRE_VERSION;
-}
-
-// Utility function to use with mock streams
-RemoteCommandResponse simulateIsMaster(RemoteCommandRequest request) {
-    ASSERT_EQ(std::string{request.cmdObj.firstElementFieldName()}, "isMaster");
-    ASSERT_EQ(request.dbname, "admin");
-
-    RemoteCommandResponse response;
-    response.data =
-        BSON("minWireVersion" << mongo::WireSpec::instance().incomingExternalClient.minWireVersion
-                              << "maxWireVersion"
-                              << mongo::WireSpec::instance().incomingExternalClient.maxWireVersion);
-    return response;
-}
-
-BSONObj objConcat(std::initializer_list<BSONObj> objs) {
-    BSONObjBuilder bob;
-
-    for (const auto& obj : objs) {
-        bob.appendElements(obj);
-    }
-
-    return bob.obj();
-}
-
-class NetworkInterfaceASIOTest : public mongo::unittest::Test {
-public:
-    void setUp() override {
-        initWireSpecMongoD();
-        NetworkInterfaceASIO::Options options;
-
-        // Use mock timer factory
-        auto timerFactory = stdx::make_unique<AsyncTimerFactoryMock>();
-        _timerFactory = timerFactory.get();
-        options.timerFactory = std::move(timerFactory);
-
-        auto factory = stdx::make_unique<AsyncMockStreamFactory>();
-        // keep unowned pointer, but pass ownership to NIA
-        _streamFactory = factory.get();
-        options.streamFactory = std::move(factory);
-        _net = stdx::make_unique<NetworkInterfaceASIO>(std::move(options));
-        _net->startup();
-    }
-
-    void tearDown() override {
-        if (!_net->inShutdown()) {
-            _net->shutdown();
-        }
-    }
-
-    Deferred<RemoteCommandResponse> startCommand(const TaskExecutor::CallbackHandle& cbHandle,
-                                                 RemoteCommandRequest& request) {
-        Deferred<RemoteCommandResponse> deferredResponse;
-        ASSERT_OK(net().startCommand(
-            cbHandle, request, [deferredResponse](ResponseStatus response) mutable {
-                deferredResponse.emplace(std::move(response));
-            }));
-        return deferredResponse;
-    }
-
-    // Helper to run startCommand and wait for it
-    RemoteCommandResponse startCommandSync(RemoteCommandRequest& request) {
-        auto deferred = startCommand(makeCallbackHandle(), request);
-
-        // wait for the operation to complete
-        auto& result = deferred.get();
-        return result;
-    }
-
-    NetworkInterfaceASIO& net() {
-        return *_net;
-    }
-
-    AsyncMockStreamFactory& streamFactory() {
-        return *_streamFactory;
-    }
-
-    AsyncTimerFactoryMock& timerFactory() {
-        return *_timerFactory;
-    }
-
-    void assertNumOps(uint64_t canceled, uint64_t timedOut, uint64_t failed, uint64_t succeeded) {
-        ASSERT_EQ(canceled, net().getNumCanceledOps());
-        ASSERT_EQ(timedOut, net().getNumTimedOutOps());
-        ASSERT_EQ(failed, net().getNumFailedOps());
-        ASSERT_EQ(succeeded, net().getNumSucceededOps());
-    }
-
-protected:
-    AsyncTimerFactoryMock* _timerFactory;
-    AsyncMockStreamFactory* _streamFactory;
-    std::unique_ptr<NetworkInterfaceASIO> _net;
-};
-
-TEST_F(NetworkInterfaceASIOTest, CancelMissingOperation) {
-    // This is just a sanity check, this action should have no effect.
-    net().cancelCommand(makeCallbackHandle());
-    assertNumOps(0u, 0u, 0u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, CancelOperation) {
-    auto cbh = makeCallbackHandle();
-
-    // Kick off our operation
-    RemoteCommandRequest request{testHost, "testDB", BSON("a" << 1), BSONObj(), nullptr};
-    auto deferred = startCommand(cbh, request);
-
-    // Create and initialize a stream so operation can begin
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-
-    // simulate isMaster reply.
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    {
-        // Cancel operation while blocked in the write for determinism. By calling cancel here we
-        // ensure that it is not a no-op and that the asio::operation_aborted error will always
-        // be returned to the NIA.
-        WriteEvent write{stream};
-        net().cancelCommand(cbh);
-    }
-
-    // Wait for op to complete, assert that it was canceled.
-    auto& result = deferred.get();
-    ASSERT_EQ(ErrorCodes::CallbackCanceled, result.status);
-    ASSERT(result.elapsedMillis);
-    assertNumOps(1u, 0u, 0u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, ImmediateCancel) {
-    auto cbh = makeCallbackHandle();
-
-    RemoteCommandRequest request{testHost, "testDB", BSON("a" << 1), BSONObj(), nullptr};
-    auto deferred = startCommand(cbh, request);
-
-    // Cancel immediately
-    net().cancelCommand(cbh);
-
-    // Allow stream to connect so operation can return
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    auto& result = deferred.get();
-    ASSERT_EQ(ErrorCodes::CallbackCanceled, result.status);
-    ASSERT(result.elapsedMillis);
-    // expect 0 completed ops because the op was canceled before getting a connection
-    assertNumOps(1u, 0u, 0u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, LateCancel) {
-    auto cbh = makeCallbackHandle();
-    RemoteCommandRequest request{testHost, "testDB", BSON("a" << 1), BSONObj(), nullptr};
-    auto deferred = startCommand(cbh, request);
-
-    // Allow stream to connect so operation can return
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    // Simulate user command
-    stream->simulateServer(rpc::Protocol::kOpMsg,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               RemoteCommandResponse response;
-                               response.data = BSONObj();
-                               response.metadata = BSONObj();
-                               return response;
-                           });
-
-    // Allow to complete, then cancel, nothing should happen.
-    auto& result = deferred.get();
-    net().cancelCommand(cbh);
-
-    ASSERT(result.isOK());
-    ASSERT(result.elapsedMillis);
-    assertNumOps(0u, 0u, 0u, 1u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, CancelWithNetworkError) {
-    auto cbh = makeCallbackHandle();
-    RemoteCommandRequest request{testHost, "testDB", BSON("a" << 1), BSONObj(), nullptr};
-    auto deferred = startCommand(cbh, request);
-
-    // Create and initialize a stream so operation can begin
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-
-    // simulate isMaster reply.
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    {
-        WriteEvent{stream}.skip();
-        ReadEvent read{stream};
-
-        // Trigger both a cancellation and a network error
-        stream->setError(make_error_code(ErrorCodes::HostUnreachable));
-        net().cancelCommand(cbh);
-    }
-
-    // Wait for op to complete, assert that cancellation error had precedence.
-    auto& result = deferred.get();
-    ASSERT(result.status == ErrorCodes::CallbackCanceled);
-    ASSERT(result.elapsedMillis);
-    assertNumOps(1u, 0u, 0u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, CancelWithTimeout) {
-    auto cbh = makeCallbackHandle();
-    RemoteCommandRequest request{testHost, "testDB", BSON("a" << 1), BSONObj(), nullptr};
-    auto deferred = startCommand(cbh, request);
-
-    // Create and initialize a stream so operation can begin
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    {
-        WriteEvent write{stream};
-
-        // Trigger both a cancellation and a timeout
-        net().cancelCommand(cbh);
-        timerFactory().fastForward(Milliseconds(500));
-    }
-
-    // Wait for op to complete, assert that cancellation error had precedence.
-    auto& result = deferred.get();
-    ASSERT_EQ(ErrorCodes::CallbackCanceled, result.status);
-    ASSERT(result.elapsedMillis);
-    assertNumOps(1u, 0u, 0u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, TimeoutWithNetworkError) {
-    auto cbh = makeCallbackHandle();
-    RemoteCommandRequest request{
-        testHost, "testDB", BSON("a" << 1), BSONObj(), nullptr, Milliseconds(1000)};
-    auto deferred = startCommand(cbh, request);
-
-    // Create and initialize a stream so operation can begin
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    {
-        WriteEvent{stream}.skip();
-        ReadEvent read{stream};
-
-        // Trigger both a timeout and a network error
-        stream->setError(make_error_code(ErrorCodes::HostUnreachable));
-        timerFactory().fastForward(Milliseconds(2000));
-    }
-
-    // Wait for op to complete, assert that timeout had precedence.
-    auto& result = deferred.get();
-    ASSERT_EQ(ErrorCodes::NetworkInterfaceExceededTimeLimit, result.status);
-    ASSERT(result.elapsedMillis);
-    assertNumOps(0u, 1u, 1u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, CancelWithTimeoutAndNetworkError) {
-    auto cbh = makeCallbackHandle();
-    RemoteCommandRequest request{
-        testHost, "testDB", BSON("a" << 1), BSONObj(), nullptr, Milliseconds(1000)};
-    auto deferred = startCommand(cbh, request);
-
-    // Create and initialize a stream so operation can begin
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    {
-        WriteEvent{stream}.skip();
-        ReadEvent read{stream};
-
-        // Trigger a timeout, a cancellation, and a network error
-        stream->setError(make_error_code(ErrorCodes::HostUnreachable));
-        timerFactory().fastForward(Milliseconds(2000));
-        net().cancelCommand(cbh);
-    }
-
-    // Wait for op to complete, assert that the cancellation had precedence.
-    auto& result = deferred.get();
-    ASSERT_EQ(ErrorCodes::CallbackCanceled, result.status);
-    ASSERT(result.elapsedMillis);
-    assertNumOps(1u, 0u, 0u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, AsyncOpTimeout) {
-    // Kick off operation
-    auto cb = makeCallbackHandle();
-    Milliseconds timeout(1000);
-    RemoteCommandRequest request{testHost, "testDB", BSON("a" << 1), BSONObj(), nullptr, timeout};
-    auto deferred = startCommand(cb, request);
-
-    // Create and initialize a stream so operation can begin
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-
-    // Simulate isMaster reply.
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    {
-        // Wait for the operation to block on write so we know it's been added.
-        WriteEvent write{stream};
-
-        // Get the timer factory
-        auto& factory = timerFactory();
-
-        // Advance clock but not enough to force a timeout, assert still active
-        factory.fastForward(Milliseconds(500));
-        ASSERT(!deferred.hasCompleted());
-
-        // Advance clock and force timeout
-        factory.fastForward(Milliseconds(500));
-    }
-
-    auto& result = deferred.get();
-    ASSERT_EQ(ErrorCodes::NetworkInterfaceExceededTimeLimit, result.status);
-    ASSERT(result.elapsedMillis);
-    assertNumOps(0u, 1u, 1u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, StartCommand) {
-    RemoteCommandRequest request{testHost, "testDB", BSON("foo" << 1), BSON("bar" << 1), nullptr};
-    auto deferred = startCommand(makeCallbackHandle(), request);
-
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-
-    // Allow stream to connect.
-    ConnectEvent{stream}.skip();
-
-    // simulate isMaster reply.
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    auto expectedMetadata = BSON("meep"
-                                 << "beep");
-    auto expectedCommandReply = BSON("boop"
-                                     << "bop"
-                                     << "ok"
-                                     << 1.0);
-
-    auto expectedCommandReplyWithMetadata = objConcat({expectedCommandReply, expectedMetadata});
-
-    // simulate user command
-    stream->simulateServer(
-        rpc::Protocol::kOpMsg, [&](RemoteCommandRequest request) -> RemoteCommandResponse {
-            ASSERT_EQ(std::string{request.cmdObj.firstElementFieldName()}, "foo");
-            ASSERT_EQ(request.dbname, "testDB");
-
-            RemoteCommandResponse response;
-            response.data = expectedCommandReply;
-            response.metadata = expectedMetadata;
-            return response;
-        });
-
-    auto& res = deferred.get();
-    ASSERT(res.elapsedMillis);
-    uassertStatusOK(res.status);
-    ASSERT_BSONOBJ_EQ(res.data, expectedCommandReplyWithMetadata);
-    ASSERT_BSONOBJ_EQ(res.metadata, expectedCommandReplyWithMetadata);
-    assertNumOps(0u, 0u, 0u, 1u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, InShutdown) {
-    ASSERT_FALSE(net().inShutdown());
-    net().shutdown();
-    ASSERT(net().inShutdown());
-}
-
-TEST_F(NetworkInterfaceASIOTest, StartCommandReturnsNotOKIfShutdownHasStarted) {
-    net().shutdown();
-    RemoteCommandRequest request;
-    ASSERT_NOT_OK(
-        net().startCommand(makeCallbackHandle(), request, [&](RemoteCommandResponse resp) {}));
-}
-
-class MalformedMessageTest : public NetworkInterfaceASIOTest {
-public:
-    using MessageHook = stdx::function<void(MsgData::View)>;
-
-    void runMessageTest(ErrorCodes::Error code, bool loadBody, MessageHook hook) {
-        // Kick off our operation
-        RemoteCommandRequest request{testHost, "testDB", BSON("ping" << 1), BSONObj(), nullptr};
-        auto deferred = startCommand(makeCallbackHandle(), request);
-
-        // Wait for it to block waiting for a write
-        auto stream = streamFactory().blockUntilStreamExists(testHost);
-        ConnectEvent{stream}.skip();
-        stream->simulateServer(rpc::Protocol::kOpQuery,
-                               [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                                   return simulateIsMaster(request);
-                               });
-
-        uint32_t messageId = 0;
-
-        {
-            // Get the appropriate message id
-            WriteEvent write{stream};
-            std::vector<uint8_t> messageData = stream->popWrite();
-            messageId =
-                MsgData::ConstView(reinterpret_cast<const char*>(messageData.data())).getId();
-        }
-
-        // Build a mock reply message
-        auto replyBuilder = rpc::makeReplyBuilder(rpc::Protocol::kOpMsg);
-        replyBuilder->setCommandReply(BSON("hello!" << 1));
-        replyBuilder->setMetadata(BSONObj());
-
-        auto message = replyBuilder->done();
-        message.header().setResponseToMsgId(messageId);
-
-        auto actualSize = message.header().getLen();
-
-        // Allow caller to mess with the Message
-        hook(message.header());
-
-        {
-            // Load the header
-            ReadEvent read{stream};
-            auto headerBytes = reinterpret_cast<const uint8_t*>(message.header().view2ptr());
-            stream->pushRead({headerBytes, headerBytes + sizeof(MSGHEADER::Value)});
-        }
-
-        if (loadBody) {
-            // Load the body if we need to
-            ReadEvent read{stream};
-            auto dataBytes = reinterpret_cast<const uint8_t*>(message.buf());
-            auto body = dataBytes;
-            std::advance(body, sizeof(MSGHEADER::Value));
-            stream->pushRead({body, dataBytes + static_cast<std::size_t>(actualSize)});
-        }
-
-        auto& response = deferred.get();
-        ASSERT_EQ(code, response.status);
-        ASSERT(response.elapsedMillis);
-        assertNumOps(0u, 0u, 1u, 0u);
-    }
-};
-
-TEST_F(MalformedMessageTest, messageHeaderWrongResponseTo) {
-    runMessageTest(ErrorCodes::ProtocolError, false, [](MsgData::View message) {
-        message.setResponseToMsgId(message.getResponseToMsgId() + 1);
-    });
-}
-
-TEST_F(MalformedMessageTest, messageHeaderlenZero) {
-    runMessageTest(
-        ErrorCodes::InvalidLength, false, [](MsgData::View message) { message.setLen(0); });
-}
-
-TEST_F(MalformedMessageTest, MessageHeaderLenTooSmall) {
-    runMessageTest(ErrorCodes::InvalidLength, false, [](MsgData::View message) {
-        message.setLen(6);
-    });  // min is 16
-}
-
-TEST_F(MalformedMessageTest, MessageHeaderLenTooLarge) {
-    runMessageTest(ErrorCodes::InvalidLength, false, [](MsgData::View message) {
-        message.setLen(48000001);
-    });  // max is 48000000
-}
-
-TEST_F(MalformedMessageTest, MessageHeaderLenNegative) {
-    runMessageTest(
-        ErrorCodes::InvalidLength, false, [](MsgData::View message) { message.setLen(-1); });
-}
-
-TEST_F(MalformedMessageTest, MessageLenSmallerThanActual) {
-    runMessageTest(ErrorCodes::InvalidBSON, true, [](MsgData::View message) {
-        message.setLen(message.getLen() - 10);
-    });
-}
-
-TEST_F(MalformedMessageTest, FailedToReadAllBytesForMessage) {
-    runMessageTest(ErrorCodes::InvalidLength, true, [](MsgData::View message) {
-        message.setLen(message.getLen() + 100);
-    });
-}
-
-TEST_F(MalformedMessageTest, UnsupportedOpcode) {
-    runMessageTest(ErrorCodes::UnsupportedFormat, true, [](MsgData::View message) {
-        message.setOperation(2222);
-    });
-}
-
-TEST_F(MalformedMessageTest, MismatchedOpcode) {
-    runMessageTest(ErrorCodes::UnsupportedFormat, true, [](MsgData::View message) {
-        message.setOperation(2006);
-    });
-}
-
-class NetworkInterfaceASIOConnectionHookTest : public NetworkInterfaceASIOTest {
-public:
-    void setUp() override {}
-
-    void start(std::unique_ptr<NetworkConnectionHook> hook) {
-        auto factory = stdx::make_unique<AsyncMockStreamFactory>();
-        // keep unowned pointer, but pass ownership to NIA
-        _streamFactory = factory.get();
-        NetworkInterfaceASIO::Options options{};
-        options.streamFactory = std::move(factory);
-        options.networkConnectionHook = std::move(hook);
-        options.timerFactory = stdx::make_unique<AsyncTimerFactoryMock>();
-        _net = stdx::make_unique<NetworkInterfaceASIO>(std::move(options));
-        _net->startup();
-    }
-};
-
-TEST_F(NetworkInterfaceASIOConnectionHookTest, InvalidIsMaster) {
-    auto validationFailedStatus =
-        Status(ErrorCodes::InterruptedDueToReplStateChange, "operation was interrupted");
-
-    start(makeTestHook(
-        [&](const HostAndPort& remoteHost, const RemoteCommandResponse& isMasterReply) {
-            return Status(ErrorCodes::UnknownError, "unused");
-        },
-        [&](const HostAndPort& remoteHost) -> StatusWith<boost::optional<RemoteCommandRequest>> {
-            return {boost::none};
-        },
-        [&](const HostAndPort& remoteHost, RemoteCommandResponse&& response) {
-            return Status::OK();
-        }));
-
-    RemoteCommandRequest request{testHost,
-                                 "blah",
-                                 BSON("foo"
-                                      << "bar"),
-                                 nullptr};
-    auto deferred = startCommand(makeCallbackHandle(), request);
-
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-
-    ConnectEvent{stream}.skip();
-
-    // simulate isMaster reply.
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               RemoteCommandResponse response;
-                               response.data = BSON("ok" << 0.0 << "errmsg"
-                                                         << "operation was interrupted"
-                                                         << "code"
-                                                         << 11602);
-                               return response;
-                           });
-
-    // we should stop here.
-    auto& res = deferred.get();
-    ASSERT_EQ(validationFailedStatus, res.status);
-    ASSERT(res.elapsedMillis);
-
-    assertNumOps(0u, 0u, 1u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOConnectionHookTest, ValidateHostInvalid) {
-    bool validateCalled = false;
-    bool hostCorrect = false;
-    bool isMasterReplyCorrect = false;
-    bool makeRequestCalled = false;
-    bool handleReplyCalled = false;
-
-    auto validationFailedStatus = Status(ErrorCodes::AlreadyInitialized, "blahhhhh");
-
-    start(makeTestHook(
-        [&](const HostAndPort& remoteHost, const RemoteCommandResponse& isMasterReply) {
-            validateCalled = true;
-            hostCorrect = (remoteHost == testHost);
-            isMasterReplyCorrect = (isMasterReply.data["TESTKEY"].str() == "TESTVALUE");
-            return validationFailedStatus;
-        },
-        [&](const HostAndPort& remoteHost) -> StatusWith<boost::optional<RemoteCommandRequest>> {
-            makeRequestCalled = true;
-            return {boost::none};
-        },
-        [&](const HostAndPort& remoteHost, RemoteCommandResponse&& response) {
-            handleReplyCalled = true;
-            return Status::OK();
-        }));
-
-    RemoteCommandRequest request{testHost,
-                                 "blah",
-                                 BSON("foo"
-                                      << "bar"),
-                                 nullptr};
-    auto deferred = startCommand(makeCallbackHandle(), request);
-
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-
-    ConnectEvent{stream}.skip();
-
-    // simulate isMaster reply.
-    stream->simulateServer(
-        rpc::Protocol::kOpQuery, [](RemoteCommandRequest request) -> RemoteCommandResponse {
-            RemoteCommandResponse response;
-            response.data =
-                BSON("minWireVersion"
-                     << mongo::WireSpec::instance().incomingExternalClient.minWireVersion
-                     << "maxWireVersion"
-                     << mongo::WireSpec::instance().incomingExternalClient.maxWireVersion
-                     << "TESTKEY"
-                     << "TESTVALUE");
-            return response;
-        });
-
-    // we should stop here.
-    auto& res = deferred.get();
-    ASSERT_EQ(validationFailedStatus, res.status);
-    ASSERT(res.elapsedMillis);
-    ASSERT(validateCalled);
-    ASSERT(hostCorrect);
-    ASSERT(isMasterReplyCorrect);
-
-    ASSERT(!makeRequestCalled);
-    ASSERT(!handleReplyCalled);
-    assertNumOps(0u, 0u, 1u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOConnectionHookTest, MakeRequestReturnsError) {
-    bool makeRequestCalled = false;
-    bool handleReplyCalled = false;
-
-    Status makeRequestError{ErrorCodes::DBPathInUse, "bloooh"};
-
-    start(makeTestHook(
-        [&](const HostAndPort& remoteHost, const RemoteCommandResponse& isMasterReply) -> Status {
-            return Status::OK();
-        },
-        [&](const HostAndPort& remoteHost) -> StatusWith<boost::optional<RemoteCommandRequest>> {
-            makeRequestCalled = true;
-            return makeRequestError;
-        },
-        [&](const HostAndPort& remoteHost, RemoteCommandResponse&& response) {
-            handleReplyCalled = true;
-            return Status::OK();
-        }));
-
-    RemoteCommandRequest request{testHost,
-                                 "blah",
-                                 BSON("foo"
-                                      << "bar"),
-                                 nullptr};
-    auto deferred = startCommand(makeCallbackHandle(), request);
-
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-
-    // simulate isMaster reply.
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    // We should stop here.
-    auto& res = deferred.get();
-
-    ASSERT_EQ(makeRequestError, res.status);
-    ASSERT(res.elapsedMillis);
-    ASSERT(makeRequestCalled);
-    ASSERT(!handleReplyCalled);
-    assertNumOps(0u, 0u, 1u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOConnectionHookTest, MakeRequestReturnsNone) {
-    bool makeRequestCalled = false;
-    bool handleReplyCalled = false;
-
-    start(makeTestHook(
-        [&](const HostAndPort& remoteHost, const RemoteCommandResponse& isMasterReply) -> Status {
-            return Status::OK();
-        },
-        [&](const HostAndPort& remoteHost) -> StatusWith<boost::optional<RemoteCommandRequest>> {
-            makeRequestCalled = true;
-            return {boost::none};
-        },
-        [&](const HostAndPort& remoteHost, RemoteCommandResponse&& response) {
-            handleReplyCalled = true;
-            return Status::OK();
-        }));
-
-    auto commandRequest = BSON("foo"
-                               << "bar");
-
-    auto commandReply = BSON("foo"
-                             << "boo"
-                             << "ok"
-                             << 1.0);
-
-    auto metadata = BSON("aaa"
-                         << "bbb");
-
-    auto commandReplyWithMetadata = objConcat({commandReply, metadata});
-
-    RemoteCommandRequest request{testHost, "blah", commandRequest, nullptr};
-    auto deferred = startCommand(makeCallbackHandle(), request);
-
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-
-    // simulate isMaster reply.
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    // Simulate user command.
-    stream->simulateServer(rpc::Protocol::kOpMsg,
-                           [&](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               ASSERT_BSONOBJ_EQ(commandRequest, request.cmdObj.removeField("$db"));
-
-                               RemoteCommandResponse response;
-                               response.data = commandReply;
-                               response.metadata = metadata;
-                               return response;
-                           });
-
-    // We should get back the reply now.
-    auto& result = deferred.get();
-
-    ASSERT(result.isOK());
-    ASSERT_BSONOBJ_EQ(commandReplyWithMetadata, result.data);
-    ASSERT(result.elapsedMillis);
-    ASSERT_BSONOBJ_EQ(commandReplyWithMetadata, result.metadata);
-    assertNumOps(0u, 0u, 0u, 1u);
-}
-
-TEST_F(NetworkInterfaceASIOConnectionHookTest, HandleReplyReturnsError) {
-    bool makeRequestCalled = false;
-
-    bool handleReplyCalled = false;
-    bool handleReplyArgumentCorrect = false;
-
-    BSONObj hookCommandRequest = BSON("1ddd"
-                                      << "fff");
-    BSONObj hookRequestMetadata = BSON("wdwd" << 1212);
-
-    BSONObj hookCommandReply = BSON("blah"
-                                    << "blah"
-                                    << "ok"
-                                    << 1.0);
-
-    BSONObj hookUnifiedRequest = ([&] {
-        BSONObjBuilder bob;
-        bob.appendElements(hookCommandRequest);
-        bob.appendElements(hookRequestMetadata);
-        bob.append("$db", "foo");
-        return bob.obj();
-    }());
-
-    BSONObj hookReplyMetadata = BSON("1111" << 2222);
-    BSONObj hookCommandReplyWithMetadata = objConcat({hookCommandReply, hookReplyMetadata});
-
-    Status handleReplyError{ErrorCodes::AuthSchemaIncompatible, "daowdjkpowkdjpow"};
-
-    start(makeTestHook(
-        [&](const HostAndPort& remoteHost, const RemoteCommandResponse& isMasterReply) -> Status {
-            return Status::OK();
-        },
-        [&](const HostAndPort& remoteHost) -> StatusWith<boost::optional<RemoteCommandRequest>> {
-            makeRequestCalled = true;
-            return {boost::make_optional<RemoteCommandRequest>(
-                {testHost, "foo", hookCommandRequest, hookRequestMetadata, nullptr})};
-
-        },
-        [&](const HostAndPort& remoteHost, RemoteCommandResponse&& response) {
-            handleReplyCalled = true;
-            handleReplyArgumentCorrect = SimpleBSONObjComparator::kInstance.evaluate(
-                                             response.data == hookCommandReplyWithMetadata) &&
-                SimpleBSONObjComparator::kInstance.evaluate(response.metadata ==
-                                                            hookCommandReplyWithMetadata);
-            return handleReplyError;
-        }));
-
-    auto commandRequest = BSON("foo"
-                               << "bar");
-    RemoteCommandRequest request{testHost, "blah", commandRequest, nullptr};
-    auto deferred = startCommand(makeCallbackHandle(), request);
-
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-
-    // simulate isMaster reply.
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    // Simulate hook reply
-    stream->simulateServer(rpc::Protocol::kOpMsg,
-                           [&](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               ASSERT_BSONOBJ_EQ(request.cmdObj, hookUnifiedRequest);
-                               ASSERT_BSONOBJ_EQ(request.metadata, BSONObj());
-
-                               RemoteCommandResponse response;
-                               response.data = hookCommandReply;
-                               response.metadata = hookReplyMetadata;
-                               return response;
-                           });
-
-    auto& result = deferred.get();
-    ASSERT_EQ(handleReplyError, result.status);
-    ASSERT(result.elapsedMillis);
-    ASSERT(makeRequestCalled);
-    ASSERT(handleReplyCalled);
-    ASSERT(handleReplyArgumentCorrect);
-    assertNumOps(0u, 0u, 1u, 0u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, SetAlarm) {
-    // set a first alarm, to execute after "expiration"
-    Date_t expiration = net().now() + Milliseconds(100);
-
-    Deferred<Date_t> deferred;
-    ASSERT_OK(net().setAlarm(
-        expiration, [this, expiration, deferred]() mutable { deferred.emplace(net().now()); }));
-
-    // Get our timer factory
-    auto& factory = timerFactory();
-
-    // force the alarm to fire
-    factory.fastForward(Milliseconds(5000));
-
-    // assert that it executed after "expiration"
-    auto& result = deferred.get();
-    ASSERT(result >= expiration);
-
-    expiration = net().now() + Milliseconds(99999999);
-    Deferred<bool> deferred2;
-    ASSERT_OK(net().setAlarm(expiration, [this, deferred2]() mutable { deferred2.emplace(true); }));
-
-    net().shutdown();
-    ASSERT(!deferred2.hasCompleted());
-}
-
-TEST_F(NetworkInterfaceASIOTest, SetAlarmReturnsNotOKIfShutdownHasStarted) {
-    net().shutdown();
-    ASSERT_NOT_OK(net().setAlarm(net().now() + Milliseconds(100), [] {}));
-}
-
-TEST_F(NetworkInterfaceASIOTest, IsMasterRequestContainsOutgoingWireVersionInternalClientInfo) {
-    WireSpec::instance().isInternalClient = true;
-
-    RemoteCommandRequest request{testHost, "testDB", BSON("ping" << 1), BSONObj(), nullptr};
-    auto deferred = startCommand(makeCallbackHandle(), request);
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-
-    // Verify that the isMaster reply has the expected internalClient data.
-    stream->simulateServer(
-        rpc::Protocol::kOpQuery, [](RemoteCommandRequest request) -> RemoteCommandResponse {
-            auto internalClientElem = request.cmdObj["internalClient"];
-            ASSERT_EQ(internalClientElem.type(), BSONType::Object);
-            auto minWireVersionElem = internalClientElem.Obj()["minWireVersion"];
-            auto maxWireVersionElem = internalClientElem.Obj()["maxWireVersion"];
-            ASSERT_EQ(minWireVersionElem.type(), BSONType::NumberInt);
-            ASSERT_EQ(maxWireVersionElem.type(), BSONType::NumberInt);
-            ASSERT_EQ(minWireVersionElem.numberInt(), WireSpec::instance().outgoing.minWireVersion);
-            ASSERT_EQ(maxWireVersionElem.numberInt(), WireSpec::instance().outgoing.maxWireVersion);
-            return simulateIsMaster(request);
-        });
-
-    // Simulate ping reply.
-    stream->simulateServer(rpc::Protocol::kOpMsg,
-                           [&](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               RemoteCommandResponse response;
-                               response.data = BSON("ok" << 1);
-                               return response;
-                           });
-
-    // Verify that the ping op is counted as a success.
-    auto& res = deferred.get();
-    ASSERT(res.elapsedMillis);
-    assertNumOps(0u, 0u, 0u, 1u);
-}
-
-TEST_F(NetworkInterfaceASIOTest, IsMasterRequestMissingInternalClientInfoWhenNotInternalClient) {
-    WireSpec::instance().isInternalClient = false;
-
-    RemoteCommandRequest request{testHost, "testDB", BSON("ping" << 1), BSONObj(), nullptr};
-    auto deferred = startCommand(makeCallbackHandle(), request);
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-
-    // Verify that the isMaster reply has the expected internalClient data.
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               ASSERT_FALSE(request.cmdObj["internalClient"]);
-                               return simulateIsMaster(request);
-                           });
-
-    // Simulate ping reply.
-    stream->simulateServer(rpc::Protocol::kOpMsg,
-                           [&](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               RemoteCommandResponse response;
-                               response.data = BSON("ok" << 1);
-                               return response;
-                           });
-
-    // Verify that the ping op is counted as a success.
-    auto& res = deferred.get();
-    ASSERT(res.elapsedMillis);
-    assertNumOps(0u, 0u, 0u, 1u);
-}
-
-class NetworkInterfaceASIOMetadataTest : public NetworkInterfaceASIOTest {
-protected:
-    void setUp() override {}
-
-    void start(std::unique_ptr<rpc::EgressMetadataHook> metadataHook) {
-        auto factory = stdx::make_unique<AsyncMockStreamFactory>();
-        _streamFactory = factory.get();
-        NetworkInterfaceASIO::Options options{};
-        options.streamFactory = std::move(factory);
-        options.metadataHook = std::move(metadataHook);
-        options.timerFactory = stdx::make_unique<AsyncTimerFactoryMock>();
-        _net = stdx::make_unique<NetworkInterfaceASIO>(std::move(options));
-        _net->startup();
-    }
-};
-
-class TestMetadataHook : public rpc::EgressMetadataHook {
-public:
-    TestMetadataHook(bool* wroteRequestMetadata, bool* gotReplyMetadata)
-        : _wroteRequestMetadata(wroteRequestMetadata), _gotReplyMetadata(gotReplyMetadata) {}
-
-    Status writeRequestMetadata(OperationContext* opCtx, BSONObjBuilder* metadataBob) override {
-        metadataBob->append("foo", "bar");
-        *_wroteRequestMetadata = true;
-        return Status::OK();
-    }
-
-    Status readReplyMetadata(OperationContext* opCtx,
-                             StringData replySource,
-                             const BSONObj& metadataObj) override {
-        *_gotReplyMetadata = (metadataObj["baz"].str() == "garply");
-        return Status::OK();
-    }
-
-private:
-    bool* _wroteRequestMetadata;
-    bool* _gotReplyMetadata;
-};
-
-TEST_F(NetworkInterfaceASIOMetadataTest, Metadata) {
-    bool wroteRequestMetadata = false;
-    bool gotReplyMetadata = false;
-    auto hookList = stdx::make_unique<rpc::EgressMetadataHookList>();
-    hookList->addHook(
-        stdx::make_unique<TestMetadataHook>(&wroteRequestMetadata, &gotReplyMetadata));
-    start(std::move(hookList));
-
-    RemoteCommandRequest request{testHost, "blah", BSON("ping" << 1), nullptr};
-    auto deferred = startCommand(makeCallbackHandle(), request);
-
-    auto stream = streamFactory().blockUntilStreamExists(testHost);
-    ConnectEvent{stream}.skip();
-
-    // simulate isMaster reply.
-    stream->simulateServer(rpc::Protocol::kOpQuery,
-                           [](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               return simulateIsMaster(request);
-                           });
-
-    // Simulate hook reply
-    stream->simulateServer(rpc::Protocol::kOpMsg,
-                           [&](RemoteCommandRequest request) -> RemoteCommandResponse {
-                               ASSERT_EQ("bar", request.cmdObj["foo"].str());
-                               RemoteCommandResponse response;
-                               response.data = BSON("ok" << 1);
-                               response.metadata = BSON("baz"
-                                                        << "garply");
-                               return response;
-                           });
-
-    auto& res = deferred.get();
-    ASSERT(res.elapsedMillis);
-    ASSERT(wroteRequestMetadata);
-    ASSERT(gotReplyMetadata);
-    assertNumOps(0u, 0u, 0u, 1u);
-}
-
-}  // namespace
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/network_interface_asio_test_utils.h b/src/mongo/executor/network_interface_asio_test_utils.h
deleted file mode 100644
index a95da3dfc5f..00000000000
--- a/src/mongo/executor/network_interface_asio_test_utils.h
+++ /dev/null
@@ -1,188 +0,0 @@
-/**
- *    Copyright (C) 2015 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-#pragma once
-
-#include <memory>
-
-#include <boost/optional.hpp>
-#include <utility>
-#include <vector>
-
-#include "mongo/executor/task_executor.h"
-#include "mongo/stdx/condition_variable.h"
-#include "mongo/stdx/future.h"
-#include "mongo/stdx/mutex.h"
-#include "mongo/util/concurrency/thread_pool_interface.h"
-
-namespace mongo {
-namespace executor {
-
-/**
- * A mock class mimicking TaskExecutor::CallbackState, does nothing.
- */
-class MockCallbackState final : public TaskExecutor::CallbackState {
-public:
-    MockCallbackState() = default;
-    void cancel() override {}
-    void waitForCompletion() override {}
-    bool isCanceled() const override {
-        return false;
-    }
-};
-
-inline TaskExecutor::CallbackHandle makeCallbackHandle() {
-    return TaskExecutor::CallbackHandle(std::make_shared<MockCallbackState>());
-}
-
-/**
- * Simple future-like utility for waiting for the result of startCommand.
- */
-template <typename T>
-class Deferred {
-public:
-    template <typename... Args>
-    void emplace(Args&&... args) {
-        _emplace(_state.get(), std::forward<Args>(args)...);
-    }
-
-    T& get() {
-        return _get(_state.get());
-    }
-
-    bool hasCompleted() {
-        stdx::unique_lock<stdx::mutex> lk(_state->mtx);
-        return _state->thing.is_initialized();
-    }
-
-    template <typename Continuation>
-    auto then(ThreadPoolInterface* pool, Continuation&& continuation)
-        -> Deferred<decltype(continuation(std::declval<Deferred<T>>().get()))> {
-        // XXX: The ugliness of the above type signature is because you can't refer to 'this' in
-        // a template parameter, at least on g++-4.8.2.
-        auto state = _state;
-        Deferred<decltype(continuation(get()))> thenDeferred;
-
-        pool->schedule([this, thenDeferred, continuation, state]() mutable {
-            thenDeferred.emplace(continuation(_get(state.get())));
-        });
-        return thenDeferred;
-    }
-
-private:
-    struct State {
-        stdx::mutex mtx;
-        stdx::condition_variable cv;
-        boost::optional<T> thing;
-    };
-
-    template <typename... Args>
-    void _emplace(State* state, Args&&... args) {
-        stdx::lock_guard<stdx::mutex> lk(_state->mtx);
-        invariant(!state->thing.is_initialized());
-        state->thing.emplace(std::forward<T>(args)...);
-        state->cv.notify_one();
-    }
-
-    T& _get(State* state) {
-        stdx::unique_lock<stdx::mutex> lk(state->mtx);
-        state->cv.wait(lk, [state] { return state->thing.is_initialized(); });
-        return *state->thing;
-    }
-
-    std::shared_ptr<State> _state = std::make_shared<State>();
-};
-
-class CountdownLatch {
-public:
-    explicit CountdownLatch(uint32_t count) : _count(count) {}
-
-    void countDown() {
-        stdx::lock_guard<stdx::mutex> lk(_mtx);
-        if (_count == 0) {
-            return;
-        }
-
-        --_count;
-        if (_count == 0) {
-            _cv.notify_all();
-        }
-    }
-
-    void await() {
-        stdx::unique_lock<stdx::mutex> lk(_mtx);
-        _cv.wait(lk, [&] { return _count == 0; });
-    }
-
-private:
-    stdx::mutex _mtx;
-    stdx::condition_variable _cv;
-    size_t _count;
-};
-
-namespace helpers {
-
-template <typename T>
-static Deferred<std::vector<T>> collect(std::vector<Deferred<T>>& ds, ThreadPoolInterface* pool) {
-    Deferred<std::vector<T>> out;
-    struct CollectState {
-        // hack to avoid requiring U to be default constructible.
-        std::vector<boost::optional<T>> mem{};
-        std::size_t numFinished = 0;
-        std::size_t goal = 0;
-        stdx::mutex mtx;
-    };
-
-    auto collectState = std::make_shared<CollectState>();
-    collectState->goal = ds.size();
-    collectState->mem.resize(collectState->goal);
-
-    for (std::size_t i = 0; i < ds.size(); ++i) {
-        ds[i].then(pool, [collectState, out, i](T res) mutable {
-            // The bool return is unused.
-            stdx::lock_guard<stdx::mutex> lk(collectState->mtx);
-            collectState->mem[i] = std::move(res);
-
-            // If we're done.
-            if (collectState->goal == ++collectState->numFinished) {
-                std::vector<T> outInitialized;
-                outInitialized.reserve(collectState->mem.size());
-                for (auto&& mem_entry : collectState->mem) {
-                    outInitialized.emplace_back(std::move(*mem_entry));
-                }
-                out.emplace(outInitialized);
-            }
-            return true;
-        });
-    }
-    return out;
-}
-
-}  // namespace helpers
-
-}  // namespace executor
-}  // namespace mongo
diff --git a/src/mongo/executor/network_interface_factory.cpp b/src/mongo/executor/network_interface_factory.cpp
index 3890e8bc64f..0f4f8526e64 100644
--- a/src/mongo/executor/network_interface_factory.cpp
+++ b/src/mongo/executor/network_interface_factory.cpp
@@ -34,16 +34,11 @@
 #include "mongo/base/status.h"
 #include "mongo/config.h"
 #include "mongo/db/server_parameters.h"
-#include "mongo/executor/async_secure_stream_factory.h"
-#include "mongo/executor/async_stream_factory.h"
-#include "mongo/executor/async_stream_interface.h"
-#include "mongo/executor/async_timer_asio.h"
 #include "mongo/executor/connection_pool.h"
 #include "mongo/executor/network_connection_hook.h"
 #include "mongo/executor/network_interface_tl.h"
 #include "mongo/rpc/metadata/metadata_hook.h"
 #include "mongo/stdx/memory.h"
-#include "mongo/util/net/ssl_manager.h"
 
 namespace mongo {
 namespace executor {
diff --git a/src/mongo/executor/network_interface_factory.h b/src/mongo/executor/network_interface_factory.h
index 7aa8a8cdce5..712cf8d812e 100644
--- a/src/mongo/executor/network_interface_factory.h
+++ b/src/mongo/executor/network_interface_factory.h
@@ -32,18 +32,13 @@
 #include <string>
 
 #include "mongo/executor/connection_pool.h"
+#include "mongo/executor/network_connection_hook.h"
 #include "mongo/executor/network_interface.h"
+#include "mongo/rpc/metadata/metadata_hook.h"
 
 namespace mongo {
-
-namespace rpc {
-class EgressMetadataHook;
-}  // namespace rpc
-
 namespace executor {
 
-class NetworkConnectionHook;
-
 /**
  * Returns a new NetworkInterface.
  */
diff --git a/src/mongo/executor/network_interface_asio_integration_fixture.cpp b/src/mongo/executor/network_interface_integration_fixture.cpp
index 0a9d8cff01b..6a593374fb6 100644
--- a/src/mongo/executor/network_interface_asio_integration_fixture.cpp
+++ b/src/mongo/executor/network_interface_integration_fixture.cpp
@@ -31,11 +31,8 @@
 #include "mongo/platform/basic.h"
 
 #include "mongo/client/connection_string.h"
-#include "mongo/executor/async_stream_factory.h"
-#include "mongo/executor/async_stream_interface.h"
-#include "mongo/executor/async_timer_asio.h"
-#include "mongo/executor/network_interface_asio.h"
-#include "mongo/executor/network_interface_asio_integration_fixture.h"
+#include "mongo/executor/network_interface_factory.h"
+#include "mongo/executor/network_interface_integration_fixture.h"
 #include "mongo/executor/remote_command_response.h"
 #include "mongo/executor/task_executor.h"
 #include "mongo/rpc/get_status_from_command_result.h"
@@ -47,62 +44,57 @@
 
 namespace mongo {
 namespace executor {
-void NetworkInterfaceASIOIntegrationFixture::startNet(NetworkInterfaceASIO::Options options) {
-    options.streamFactory = stdx::make_unique<AsyncStreamFactory>();
-    options.timerFactory = stdx::make_unique<AsyncTimerFactoryASIO>();
+
+void NetworkInterfaceIntegrationFixture::startNet(
+    std::unique_ptr<NetworkConnectionHook> connectHook) {
+    ConnectionPool::Options options;
 #ifdef _WIN32
     // Connections won't queue on widnows, so attempting to open too many connections
     // concurrently will result in refused connections and test failure.
-    options.connectionPoolOptions.maxConnections = 16u;
+    options.maxConnections = 16u;
 #else
-    options.connectionPoolOptions.maxConnections = 256u;
+    options.maxConnections = 256u;
 #endif
-    _net = stdx::make_unique<NetworkInterfaceASIO>(std::move(options));
+    _net = makeNetworkInterface(
+        "NetworkInterfaceIntegrationFixture", std::move(connectHook), nullptr, std::move(options));
+
     _net->startup();
 }
 
-void NetworkInterfaceASIOIntegrationFixture::tearDown() {
+void NetworkInterfaceIntegrationFixture::tearDown() {
     if (!_net->inShutdown()) {
         _net->shutdown();
     }
 }
 
-NetworkInterfaceASIO& NetworkInterfaceASIOIntegrationFixture::net() {
+NetworkInterface& NetworkInterfaceIntegrationFixture::net() {
     return *_net;
 }
 
-ConnectionString NetworkInterfaceASIOIntegrationFixture::fixture() {
+ConnectionString NetworkInterfaceIntegrationFixture::fixture() {
     return unittest::getFixtureConnectionString();
 }
 
-void NetworkInterfaceASIOIntegrationFixture::setRandomNumberGenerator(PseudoRandom* generator) {
+void NetworkInterfaceIntegrationFixture::setRandomNumberGenerator(PseudoRandom* generator) {
     _rng = generator;
 }
 
-PseudoRandom* NetworkInterfaceASIOIntegrationFixture::getRandomNumberGenerator() {
+PseudoRandom* NetworkInterfaceIntegrationFixture::getRandomNumberGenerator() {
     return _rng;
 }
 
-void NetworkInterfaceASIOIntegrationFixture::startCommand(
-    const TaskExecutor::CallbackHandle& cbHandle,
-    RemoteCommandRequest& request,
-    StartCommandCB onFinish) {
+void NetworkInterfaceIntegrationFixture::startCommand(const TaskExecutor::CallbackHandle& cbHandle,
+                                                      RemoteCommandRequest& request,
+                                                      StartCommandCB onFinish) {
     net().startCommand(cbHandle, request, onFinish).transitional_ignore();
 }
 
-Deferred<RemoteCommandResponse> NetworkInterfaceASIOIntegrationFixture::runCommand(
-    const TaskExecutor::CallbackHandle& cbHandle, RemoteCommandRequest& request) {
-    Deferred<RemoteCommandResponse> deferred;
-    net()
-        .startCommand(
-            cbHandle,
-            request,
-            [deferred](RemoteCommandResponse resp) mutable { deferred.emplace(std::move(resp)); })
-        .transitional_ignore();
-    return deferred;
+Future<RemoteCommandResponse> NetworkInterfaceIntegrationFixture::runCommand(
+    const TaskExecutor::CallbackHandle& cbHandle, RemoteCommandRequest request) {
+    return net().startCommand(cbHandle, request);
 }
 
-RemoteCommandResponse NetworkInterfaceASIOIntegrationFixture::runCommandSync(
+RemoteCommandResponse NetworkInterfaceIntegrationFixture::runCommandSync(
     RemoteCommandRequest& request) {
     auto deferred = runCommand(makeCallbackHandle(), request);
     auto& res = deferred.get();
@@ -114,9 +106,9 @@ RemoteCommandResponse NetworkInterfaceASIOIntegrationFixture::runCommandSync(
     return res;
 }
 
-void NetworkInterfaceASIOIntegrationFixture::assertCommandOK(StringData db,
-                                                             const BSONObj& cmd,
-                                                             Milliseconds timeoutMillis) {
+void NetworkInterfaceIntegrationFixture::assertCommandOK(StringData db,
+                                                         const BSONObj& cmd,
+                                                         Milliseconds timeoutMillis) {
     RemoteCommandRequest request{
         fixture().getServers()[0], db.toString(), cmd, BSONObj(), nullptr, timeoutMillis};
     auto res = runCommandSync(request);
@@ -125,16 +117,20 @@ void NetworkInterfaceASIOIntegrationFixture::assertCommandOK(StringData db,
     ASSERT(!res.data["writeErrors"]);
 }
 
-void NetworkInterfaceASIOIntegrationFixture::assertCommandFailsOnClient(
-    StringData db, const BSONObj& cmd, ErrorCodes::Error reason, Milliseconds timeoutMillis) {
+void NetworkInterfaceIntegrationFixture::assertCommandFailsOnClient(StringData db,
+                                                                    const BSONObj& cmd,
+                                                                    ErrorCodes::Error reason,
+                                                                    Milliseconds timeoutMillis) {
     RemoteCommandRequest request{
         fixture().getServers()[0], db.toString(), cmd, BSONObj(), nullptr, timeoutMillis};
     auto res = runCommandSync(request);
     ASSERT_EQ(reason, res.status.code());
 }
 
-void NetworkInterfaceASIOIntegrationFixture::assertCommandFailsOnServer(
-    StringData db, const BSONObj& cmd, ErrorCodes::Error reason, Milliseconds timeoutMillis) {
+void NetworkInterfaceIntegrationFixture::assertCommandFailsOnServer(StringData db,
+                                                                    const BSONObj& cmd,
+                                                                    ErrorCodes::Error reason,
+                                                                    Milliseconds timeoutMillis) {
     RemoteCommandRequest request{
         fixture().getServers()[0], db.toString(), cmd, BSONObj(), nullptr, timeoutMillis};
     auto res = runCommandSync(request);
@@ -143,10 +139,10 @@ void NetworkInterfaceASIOIntegrationFixture::assertCommandFailsOnServer(
     ASSERT_EQ(reason, serverStatus);
 }
 
-void NetworkInterfaceASIOIntegrationFixture::assertWriteError(StringData db,
-                                                              const BSONObj& cmd,
-                                                              ErrorCodes::Error reason,
-                                                              Milliseconds timeoutMillis) {
+void NetworkInterfaceIntegrationFixture::assertWriteError(StringData db,
+                                                          const BSONObj& cmd,
+                                                          ErrorCodes::Error reason,
+                                                          Milliseconds timeoutMillis) {
     RemoteCommandRequest request{
         fixture().getServers()[0], db.toString(), cmd, BSONObj(), nullptr, timeoutMillis};
     auto res = runCommandSync(request);
@@ -158,5 +154,6 @@ void NetworkInterfaceASIOIntegrationFixture::assertWriteError(StringData db,
                             firstWriteError.getStringField("errmsg"));
     ASSERT_EQ(reason, writeErrorStatus);
 }
+
 }  // namespace executor
 }  // namespace mongo
diff --git a/src/mongo/executor/network_interface_asio_integration_fixture.h b/src/mongo/executor/network_interface_integration_fixture.h
index f6207e7a12c..a83a5d06f31 100644
--- a/src/mongo/executor/network_interface_asio_integration_fixture.h
+++ b/src/mongo/executor/network_interface_integration_fixture.h
@@ -29,9 +29,11 @@
 
 #include "mongo/unittest/unittest.h"
 
-#include "mongo/executor/network_interface_asio.h"
-#include "mongo/executor/network_interface_asio_test_utils.h"
+#include "mongo/client/connection_string.h"
+#include "mongo/executor/network_connection_hook.h"
+#include "mongo/executor/network_interface.h"
 #include "mongo/executor/task_executor.h"
+#include "mongo/util/future.h"
 
 namespace mongo {
 
@@ -39,14 +41,31 @@ class PseudoRandom;
 
 namespace executor {
 
+/**
+ * A mock class mimicking TaskExecutor::CallbackState, does nothing.
+ */
+class MockCallbackState final : public TaskExecutor::CallbackState {
+public:
+    MockCallbackState() = default;
+    void cancel() override {}
+    void waitForCompletion() override {}
+    bool isCanceled() const override {
+        return false;
+    }
+};
+
+inline TaskExecutor::CallbackHandle makeCallbackHandle() {
+    return TaskExecutor::CallbackHandle(std::make_shared<MockCallbackState>());
+}
+
 using StartCommandCB = stdx::function<void(const RemoteCommandResponse&)>;
 
-class NetworkInterfaceASIOIntegrationFixture : public mongo::unittest::Test {
+class NetworkInterfaceIntegrationFixture : public mongo::unittest::Test {
 public:
-    void startNet(NetworkInterfaceASIO::Options options = NetworkInterfaceASIO::Options());
+    void startNet(std::unique_ptr<NetworkConnectionHook> connectHook = nullptr);
     void tearDown() override;
 
-    NetworkInterfaceASIO& net();
+    NetworkInterface& net();
 
     ConnectionString fixture();
 
@@ -58,8 +77,8 @@ public:
                       RemoteCommandRequest& request,
                       StartCommandCB onFinish);
 
-    Deferred<RemoteCommandResponse> runCommand(const TaskExecutor::CallbackHandle& cbHandle,
-                                               RemoteCommandRequest& request);
+    Future<RemoteCommandResponse> runCommand(const TaskExecutor::CallbackHandle& cbHandle,
+                                             RemoteCommandRequest request);
 
     RemoteCommandResponse runCommandSync(RemoteCommandRequest& request);
 
@@ -82,7 +101,7 @@ public:
                           Milliseconds timeoutMillis = Minutes(5));
 
 private:
-    std::unique_ptr<NetworkInterfaceASIO> _net;
+    std::unique_ptr<NetworkInterface> _net;
     PseudoRandom* _rng = nullptr;
 };
 }  // namespace executor
diff --git a/src/mongo/executor/network_interface_integration_test.cpp b/src/mongo/executor/network_interface_integration_test.cpp
new file mode 100644
index 00000000000..b5a9d08edeb
--- /dev/null
+++ b/src/mongo/executor/network_interface_integration_test.cpp
@@ -0,0 +1,373 @@
+/**
+ *    Copyright (C) 2015 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kNetwork
+
+#include "mongo/platform/basic.h"
+
+#include <algorithm>
+#include <exception>
+
+#include "mongo/base/status_with.h"
+#include "mongo/client/connection_string.h"
+#include "mongo/db/commands/test_commands_enabled.h"
+#include "mongo/db/wire_version.h"
+#include "mongo/executor/network_connection_hook.h"
+#include "mongo/executor/network_interface_integration_fixture.h"
+#include "mongo/executor/test_network_connection_hook.h"
+#include "mongo/rpc/factory.h"
+#include "mongo/rpc/get_status_from_command_result.h"
+#include "mongo/rpc/message.h"
+#include "mongo/stdx/future.h"
+#include "mongo/stdx/memory.h"
+#include "mongo/unittest/integration_test.h"
+#include "mongo/unittest/unittest.h"
+#include "mongo/util/assert_util.h"
+#include "mongo/util/log.h"
+#include "mongo/util/scopeguard.h"
+
+namespace mongo {
+namespace executor {
+namespace {
+
+bool pingCommandMissing(const RemoteCommandResponse& result) {
+    if (result.isOK()) {
+        // On mongos, there is no sleep command, so just check that the command failed with
+        // a "Command not found" error code
+        ASSERT_EQ(result.data["ok"].Double(), 0.0);
+        ASSERT_EQ(result.data["code"].Int(), 59);
+        return true;
+    }
+
+    return false;
+}
+
+TEST_F(NetworkInterfaceIntegrationFixture, Ping) {
+    startNet();
+    assertCommandOK("admin", BSON("ping" << 1));
+}
+
+// Hook that intentionally never finishes
+class HangingHook : public executor::NetworkConnectionHook {
+    Status validateHost(const HostAndPort&,
+                        const BSONObj& request,
+                        const RemoteCommandResponse&) final {
+        return Status::OK();
+    }
+
+    StatusWith<boost::optional<RemoteCommandRequest>> makeRequest(
+        const HostAndPort& remoteHost) final {
+        return {boost::make_optional(RemoteCommandRequest(remoteHost,
+                                                          "admin",
+                                                          BSON("sleep" << 1 << "lock"
+                                                                       << "none"
+                                                                       << "secs"
+                                                                       << 100000000),
+                                                          BSONObj(),
+                                                          nullptr))};
+    }
+
+    Status handleReply(const HostAndPort& remoteHost, RemoteCommandResponse&& response) final {
+        if (pingCommandMissing(response)) {
+            return {ErrorCodes::NetworkInterfaceExceededTimeLimit,
+                    "No ping command. Simulating timeout"};
+        }
+
+        MONGO_UNREACHABLE;
+    }
+};
+
+
+// Test that we time out a command if the connection hook hangs.
+TEST_F(NetworkInterfaceIntegrationFixture, HookHangs) {
+    startNet(stdx::make_unique<HangingHook>());
+
+    assertCommandFailsOnClient(
+        "admin", BSON("ping" << 1), ErrorCodes::NetworkInterfaceExceededTimeLimit, Seconds(1));
+}
+
+using ResponseStatus = TaskExecutor::ResponseStatus;
+
+BSONObj objConcat(std::initializer_list<BSONObj> objs) {
+    BSONObjBuilder bob;
+
+    for (const auto& obj : objs) {
+        bob.appendElements(obj);
+    }
+
+    return bob.obj();
+}
+
+class NetworkInterfaceTest : public NetworkInterfaceIntegrationFixture {
+public:
+    void assertNumOps(uint64_t canceled, uint64_t timedOut, uint64_t failed, uint64_t succeeded) {
+        auto counters = net().getCounters();
+        ASSERT_EQ(canceled, counters.canceled);
+        ASSERT_EQ(timedOut, counters.timedOut);
+        ASSERT_EQ(failed, counters.failed);
+        ASSERT_EQ(succeeded, counters.succeeded);
+    }
+
+    void setUp() override {
+        setTestCommandsEnabled(true);
+        startNet(std::make_unique<WaitForIsMasterHook>(this));
+    }
+
+    RemoteCommandRequest makeTestCommand(boost::optional<Milliseconds> timeout = boost::none,
+                                         BSONObj cmd = BSON("echo" << 1 << "foo"
+                                                                   << "bar")) {
+        auto cs = fixture();
+        return RemoteCommandRequest(cs.getServers().front(),
+                                    "admin",
+                                    std::move(cmd),
+                                    BSONObj(),
+                                    nullptr,
+                                    timeout ? *timeout : RemoteCommandRequest::kNoTimeout);
+    }
+
+    struct IsMasterData {
+        BSONObj request;
+        RemoteCommandResponse response;
+    };
+    IsMasterData waitForIsMaster() {
+        stdx::unique_lock<stdx::mutex> lk(_mutex);
+        _isMasterCond.wait(lk, [this] { return _isMasterResult != boost::none; });
+
+        return std::move(*_isMasterResult);
+    }
+
+    bool hasIsMaster() {
+        stdx::lock_guard<stdx::mutex> lk(_mutex);
+        return _isMasterResult != boost::none;
+    }
+
+private:
+    class WaitForIsMasterHook : public NetworkConnectionHook {
+    public:
+        explicit WaitForIsMasterHook(NetworkInterfaceTest* parent) : _parent(parent) {}
+
+        Status validateHost(const HostAndPort& host,
+                            const BSONObj& request,
+                            const RemoteCommandResponse& isMasterReply) override {
+            stdx::lock_guard<stdx::mutex> lk(_parent->_mutex);
+            _parent->_isMasterResult = {request, isMasterReply};
+            _parent->_isMasterCond.notify_all();
+            return Status::OK();
+        }
+
+        StatusWith<boost::optional<RemoteCommandRequest>> makeRequest(const HostAndPort&) override {
+            return {boost::none};
+        }
+
+        Status handleReply(const HostAndPort&, RemoteCommandResponse&&) override {
+            return Status::OK();
+        }
+
+    private:
+        NetworkInterfaceTest* _parent;
+    };
+
+    stdx::mutex _mutex;
+    stdx::condition_variable _isMasterCond;
+    boost::optional<IsMasterData> _isMasterResult;
+};
+
+TEST_F(NetworkInterfaceTest, CancelMissingOperation) {
+    // This is just a sanity check, this action should have no effect.
+    net().cancelCommand(makeCallbackHandle());
+    assertNumOps(0u, 0u, 0u, 0u);
+}
+
+TEST_F(NetworkInterfaceTest, CancelOperation) {
+    auto cbh = makeCallbackHandle();
+
+    // Kick off our operation
+    FailPointEnableBlock fpb("networkInterfaceDiscardCommandsAfterAcquireConn");
+
+    auto deferred = runCommand(cbh, makeTestCommand());
+
+    waitForIsMaster();
+
+    net().cancelCommand(cbh);
+
+    // Wait for op to complete, assert that it was canceled.
+    auto result = deferred.get();
+    ASSERT_EQ(ErrorCodes::CallbackCanceled, result.status);
+    ASSERT(result.elapsedMillis);
+    assertNumOps(1u, 0u, 0u, 0u);
+}
+
+TEST_F(NetworkInterfaceTest, ImmediateCancel) {
+    auto cbh = makeCallbackHandle();
+
+    // Kick off our operation
+
+    FailPointEnableBlock fpb("networkInterfaceDiscardCommandsBeforeAcquireConn");
+
+    auto deferred = runCommand(cbh, makeTestCommand());
+
+    net().cancelCommand(cbh);
+
+    ASSERT_FALSE(hasIsMaster());
+
+    // Wait for op to complete, assert that it was canceled.
+    auto result = deferred.get();
+    ASSERT_EQ(ErrorCodes::CallbackCanceled, result.status);
+    ASSERT(result.elapsedMillis);
+    assertNumOps(1u, 0u, 0u, 0u);
+}
+
+TEST_F(NetworkInterfaceTest, LateCancel) {
+    auto cbh = makeCallbackHandle();
+
+    auto deferred = runCommand(cbh, makeTestCommand());
+
+    // Wait for op to complete, assert that it was canceled.
+    auto result = deferred.get();
+    net().cancelCommand(cbh);
+
+    ASSERT(result.isOK());
+    ASSERT(result.elapsedMillis);
+    assertNumOps(0u, 0u, 0u, 1u);
+}
+
+TEST_F(NetworkInterfaceTest, AsyncOpTimeout) {
+    // Kick off operation
+    auto cb = makeCallbackHandle();
+    auto request = makeTestCommand(Milliseconds{1000});
+    request.cmdObj = BSON("sleep" << 1 << "lock"
+                                  << "none"
+                                  << "secs"
+                                  << 1000000000);
+    auto deferred = runCommand(cb, request);
+
+    waitForIsMaster();
+
+    auto result = deferred.get();
+
+    // mongos doesn't implement the ping command, so ignore the response there, otherwise
+    // check that we've timed out.
+    if (!pingCommandMissing(result)) {
+        ASSERT_EQ(ErrorCodes::NetworkInterfaceExceededTimeLimit, result.status);
+        ASSERT(result.elapsedMillis);
+        assertNumOps(0u, 1u, 0u, 0u);
+    }
+}
+
+TEST_F(NetworkInterfaceTest, StartCommand) {
+    auto commandRequest = BSON("echo" << 1 << "boop"
+                                      << "bop");
+
+    // This opmsg request expect the following reply, which is generated below
+    // { echo: { echo: 1, boop: "bop", $db: "admin" }, ok: 1.0 }
+    auto expectedCommandReply = [&] {
+        BSONObjBuilder echoed;
+        echoed.appendElements(commandRequest);
+        echoed << "$db"
+               << "admin";
+        return echoed.obj();
+    }();
+    auto request = makeTestCommand(boost::none, commandRequest);
+
+    auto deferred = runCommand(makeCallbackHandle(), std::move(request));
+
+    auto res = deferred.get();
+
+    ASSERT(res.elapsedMillis);
+    uassertStatusOK(res.status);
+    ASSERT_BSONOBJ_EQ(res.data.getObjectField("echo"), expectedCommandReply);
+    ASSERT_EQ(res.data.getIntField("ok"), 1);
+    assertNumOps(0u, 0u, 0u, 1u);
+}
+
+TEST_F(NetworkInterfaceTest, SetAlarm) {
+    // set a first alarm, to execute after "expiration"
+    Date_t expiration = net().now() + Milliseconds(100);
+    auto makeTimerFuture = [&] {
+        Promise<Date_t> promise;
+        auto future = promise.getFuture();
+
+        return std::make_pair(
+            [ this, promise = promise.share() ]() mutable { promise.emplaceValue(net().now()); },
+            std::move(future));
+    };
+
+    auto futurePair = makeTimerFuture();
+    ASSERT_OK(net().setAlarm(expiration, std::move(futurePair.first)));
+
+    // assert that it executed after "expiration"
+    auto& result = futurePair.second.get();
+    ASSERT(result >= expiration);
+
+    expiration = net().now() + Milliseconds(99999999);
+    auto futurePair2 = makeTimerFuture();
+    ASSERT_OK(net().setAlarm(expiration, std::move(futurePair2.first)));
+
+    net().shutdown();
+    ASSERT_TRUE(!futurePair2.second.isReady());
+}
+
+TEST_F(NetworkInterfaceTest, IsMasterRequestContainsOutgoingWireVersionInternalClientInfo) {
+    WireSpec::instance().isInternalClient = true;
+
+    auto deferred = runCommand(makeCallbackHandle(), makeTestCommand());
+    auto isMasterHandshake = waitForIsMaster();
+
+    // Verify that the isMaster reply has the expected internalClient data.
+    auto internalClientElem = isMasterHandshake.request["internalClient"];
+    ASSERT_EQ(internalClientElem.type(), BSONType::Object);
+    auto minWireVersionElem = internalClientElem.Obj()["minWireVersion"];
+    auto maxWireVersionElem = internalClientElem.Obj()["maxWireVersion"];
+    ASSERT_EQ(minWireVersionElem.type(), BSONType::NumberInt);
+    ASSERT_EQ(maxWireVersionElem.type(), BSONType::NumberInt);
+    ASSERT_EQ(minWireVersionElem.numberInt(), WireSpec::instance().outgoing.minWireVersion);
+    ASSERT_EQ(maxWireVersionElem.numberInt(), WireSpec::instance().outgoing.maxWireVersion);
+
+    // Verify that the ping op is counted as a success.
+    auto res = deferred.get();
+    ASSERT(res.elapsedMillis);
+    assertNumOps(0u, 0u, 0u, 1u);
+}
+
+TEST_F(NetworkInterfaceTest, IsMasterRequestMissingInternalClientInfoWhenNotInternalClient) {
+    WireSpec::instance().isInternalClient = false;
+
+    auto deferred = runCommand(makeCallbackHandle(), makeTestCommand());
+    auto isMasterHandshake = waitForIsMaster();
+
+    // Verify that the isMaster reply has the expected internalClient data.
+    ASSERT_FALSE(isMasterHandshake.request["internalClient"]);
+    // Verify that the ping op is counted as a success.
+    auto res = deferred.get();
+    ASSERT(res.elapsedMillis);
+    assertNumOps(0u, 0u, 0u, 1u);
+}
+
+}  // namespace
+}  // namespace executor
+}  // namespace mongo
diff --git a/src/mongo/executor/network_interface_mock.cpp b/src/mongo/executor/network_interface_mock.cpp
index 674dd8bb116..42cda1b4005 100644
--- a/src/mongo/executor/network_interface_mock.cpp
+++ b/src/mongo/executor/network_interface_mock.cpp
@@ -481,7 +481,7 @@ void NetworkInterfaceMock::_connectThenEnqueueOperation_inlock(const HostAndPort
         ? handshakeReplyIter->second
         : RemoteCommandResponse(BSONObj(), BSONObj(), Milliseconds(0));
 
-    auto valid = _hook->validateHost(target, handshakeReply);
+    auto valid = _hook->validateHost(target, op.getRequest().cmdObj, handshakeReply);
     if (!valid.isOK()) {
         op.setResponse(_now_inlock(), valid);
         op.finishResponse();
diff --git a/src/mongo/executor/network_interface_mock.h b/src/mongo/executor/network_interface_mock.h
index 76a9a6462a8..fdb5b58d50c 100644
--- a/src/mongo/executor/network_interface_mock.h
+++ b/src/mongo/executor/network_interface_mock.h
@@ -84,6 +84,9 @@ public:
     virtual ~NetworkInterfaceMock();
     virtual void appendConnectionStats(ConnectionPoolStats* stats) const;
     virtual std::string getDiagnosticString();
+    Counters getCounters() const override {
+        return Counters();
+    }
 
     /**
      * Logs the contents of the queues for diagnostics.
diff --git a/src/mongo/executor/network_interface_mock_test.cpp b/src/mongo/executor/network_interface_mock_test.cpp
index 59c33e1fc82..a09ed4aeac0 100644
--- a/src/mongo/executor/network_interface_mock_test.cpp
+++ b/src/mongo/executor/network_interface_mock_test.cpp
@@ -133,7 +133,9 @@ TEST_F(NetworkInterfaceMockTest, ConnectionHook) {
     // Since the contract of these methods is that they do not throw, we run the ASSERTs in
     // the test scope.
     net().setConnectionHook(makeTestHook(
-        [&](const HostAndPort& remoteHost, const RemoteCommandResponse& isMasterReply) {
+        [&](const HostAndPort& remoteHost,
+            const BSONObj&,
+            const RemoteCommandResponse& isMasterReply) {
             validateCalled = true;
             hostCorrectForValidate = (remoteHost == testHost());
             replyCorrectForValidate = SimpleBSONObjComparator::kInstance.evaluate(
@@ -219,7 +221,9 @@ TEST_F(NetworkInterfaceMockTest, ConnectionHook) {
 
 TEST_F(NetworkInterfaceMockTest, ConnectionHookFailedValidation) {
     net().setConnectionHook(makeTestHook(
-        [&](const HostAndPort& remoteHost, const RemoteCommandResponse& isMasterReply) -> Status {
+        [&](const HostAndPort& remoteHost,
+            const BSONObj&,
+            const RemoteCommandResponse& isMasterReply) -> Status {
             // We just need some obscure non-OK code.
             return {ErrorCodes::ConflictingOperationInProgress, "blah"};
         },
@@ -260,9 +264,9 @@ TEST_F(NetworkInterfaceMockTest, ConnectionHookFailedValidation) {
 TEST_F(NetworkInterfaceMockTest, ConnectionHookNoRequest) {
     bool makeRequestCalled = false;
     net().setConnectionHook(makeTestHook(
-        [&](const HostAndPort& remoteHost, const RemoteCommandResponse& isMasterReply) -> Status {
-            return Status::OK();
-        },
+        [&](const HostAndPort& remoteHost,
+            const BSONObj&,
+            const RemoteCommandResponse& isMasterReply) -> Status { return Status::OK(); },
         [&](const HostAndPort& remoteHost) -> StatusWith<boost::optional<RemoteCommandRequest>> {
             makeRequestCalled = true;
             return {boost::none};
@@ -296,9 +300,9 @@ TEST_F(NetworkInterfaceMockTest, ConnectionHookNoRequest) {
 TEST_F(NetworkInterfaceMockTest, ConnectionHookMakeRequestFails) {
     bool makeRequestCalled = false;
     net().setConnectionHook(makeTestHook(
-        [&](const HostAndPort& remoteHost, const RemoteCommandResponse& isMasterReply) -> Status {
-            return Status::OK();
-        },
+        [&](const HostAndPort& remoteHost,
+            const BSONObj&,
+            const RemoteCommandResponse& isMasterReply) -> Status { return Status::OK(); },
         [&](const HostAndPort& remoteHost) -> StatusWith<boost::optional<RemoteCommandRequest>> {
             makeRequestCalled = true;
             return {ErrorCodes::InvalidSyncSource, "blah"};
@@ -333,9 +337,9 @@ TEST_F(NetworkInterfaceMockTest, ConnectionHookMakeRequestFails) {
 TEST_F(NetworkInterfaceMockTest, ConnectionHookHandleReplyFails) {
     bool handleReplyCalled = false;
     net().setConnectionHook(makeTestHook(
-        [&](const HostAndPort& remoteHost, const RemoteCommandResponse& isMasterReply) -> Status {
-            return Status::OK();
-        },
+        [&](const HostAndPort& remoteHost,
+            const BSONObj&,
+            const RemoteCommandResponse& isMasterReply) -> Status { return Status::OK(); },
         [&](const HostAndPort& remoteHost) -> StatusWith<boost::optional<RemoteCommandRequest>> {
             return boost::make_optional<RemoteCommandRequest>({});
         },
diff --git a/src/mongo/executor/network_interface_tl.cpp b/src/mongo/executor/network_interface_tl.cpp
index 62111f3f1b8..5fb164cf9e6 100644
--- a/src/mongo/executor/network_interface_tl.cpp
+++ b/src/mongo/executor/network_interface_tl.cpp
@@ -32,6 +32,7 @@
 
 #include "mongo/executor/network_interface_tl.h"
 
+#include "mongo/db/commands/test_commands_enabled.h"
 #include "mongo/db/server_options.h"
 #include "mongo/executor/connection_pool_tl.h"
 #include "mongo/transport/transport_layer_manager.h"
@@ -70,6 +71,12 @@ void NetworkInterfaceTL::appendConnectionStats(ConnectionPoolStats* stats) const
         pool->appendConnectionStats(stats);
 }
 
+NetworkInterface::Counters NetworkInterfaceTL::getCounters() const {
+    invariant(getTestCommandsEnabled());
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+    return _counters;
+}
+
 std::string NetworkInterfaceTL::getHostName() {
     return getHostNameCached();
 }
@@ -174,6 +181,15 @@ Status NetworkInterfaceTL::startCommand(const TaskExecutor::CallbackHandle& cbHa
         state->deadline = state->start + state->request.timeout;
     }
 
+    if (MONGO_FAIL_POINT(networkInterfaceDiscardCommandsBeforeAcquireConn)) {
+        log() << "Discarding command due to failpoint before acquireConn";
+        std::move(state->mergedFuture)
+            .getAsync([onFinish](StatusWith<RemoteCommandResponse> response) {
+                onFinish(RemoteCommandResponse(response.getStatus(), Milliseconds{0}));
+            });
+        return Status::OK();
+    }
+
     // Interacting with the connection pool can involve more work than just getting a connection
     // out.  In particular, we can end up having to spin up new connections, and fulfilling promises
     // for other requesters.  Returning connections has the same issue.
@@ -254,6 +270,11 @@ Future<RemoteCommandResponse> NetworkInterfaceTL::_onAcquireConn(
     std::shared_ptr<CommandState> state,
     CommandState::ConnHandle conn,
     const transport::BatonHandle& baton) {
+    if (MONGO_FAIL_POINT(networkInterfaceDiscardCommandsAfterAcquireConn)) {
+        conn->indicateSuccess();
+        return std::move(state->mergedFuture);
+    }
+
     if (state->done.load()) {
         conn->indicateSuccess();
         uasserted(ErrorCodes::CallbackCanceled, "Command was canceled");
@@ -277,7 +298,7 @@ Future<RemoteCommandResponse> NetworkInterfaceTL::_onAcquireConn(
 
         state->timer = _reactor->makeTimer();
         state->timer->waitUntil(state->deadline, baton)
-            .getAsync([client, state, baton](Status status) {
+            .getAsync([this, client, state, baton](Status status) {
                 if (status == ErrorCodes::CallbackCanceled) {
                     invariant(state->done.load());
                     return;
@@ -287,6 +308,11 @@ Future<RemoteCommandResponse> NetworkInterfaceTL::_onAcquireConn(
                     return;
                 }
 
+                if (getTestCommandsEnabled()) {
+                    stdx::lock_guard<stdx::mutex> lk(_mutex);
+                    _counters.timedOut++;
+                }
+
                 LOG(2) << "Request " << state->request.id << " timed out"
                        << ", deadline was " << state->deadline << ", op was "
                        << redact(state->request.toString());
@@ -324,6 +350,15 @@ Future<RemoteCommandResponse> NetworkInterfaceTL::_onAcquireConn(
             if (state->done.swap(true))
                 return;
 
+            if (getTestCommandsEnabled()) {
+                stdx::lock_guard<stdx::mutex> lk(_mutex);
+                if (swr.isOK() && swr.getValue().status.isOK()) {
+                    _counters.succeeded++;
+                } else {
+                    _counters.failed++;
+                }
+            }
+
             if (state->timer) {
                 state->timer->cancel(baton);
             }
@@ -354,6 +389,11 @@ void NetworkInterfaceTL::cancelCommand(const TaskExecutor::CallbackHandle& cbHan
         return;
     }
 
+    if (getTestCommandsEnabled()) {
+        stdx::lock_guard<stdx::mutex> lk(_mutex);
+        _counters.canceled++;
+    }
+
     LOG(2) << "Canceling operation; original request was: " << redact(state->request.toString());
     state->promise.setError({ErrorCodes::CallbackCanceled,
                              str::stream() << "Command canceled; original request was: "
diff --git a/src/mongo/executor/network_interface_tl.h b/src/mongo/executor/network_interface_tl.h
index 76053a511d7..b3e3296d8dc 100644
--- a/src/mongo/executor/network_interface_tl.h
+++ b/src/mongo/executor/network_interface_tl.h
@@ -54,6 +54,8 @@ public:
     std::string getDiagnosticString() override;
     void appendConnectionStats(ConnectionPoolStats* stats) const override;
     std::string getHostName() override;
+    Counters getCounters() const override;
+
     void startup() override;
     void shutdown() override;
     bool inShutdown() const override;
@@ -121,6 +123,7 @@ private:
     ConnectionPool::Options _connPoolOpts;
     std::unique_ptr<NetworkConnectionHook> _onConnectHook;
     std::unique_ptr<ConnectionPool> _pool;
+    Counters _counters;
 
     std::unique_ptr<rpc::EgressMetadataHook> _metadataHook;
     AtomicBool _inShutdown;
diff --git a/src/mongo/executor/test_network_connection_hook.h b/src/mongo/executor/test_network_connection_hook.h
index 0294b23cd38..b78379d3919 100644
--- a/src/mongo/executor/test_network_connection_hook.h
+++ b/src/mongo/executor/test_network_connection_hook.h
@@ -52,8 +52,9 @@ public:
           _replyFunc(std::forward<ReplyFunc>(replyFunc)) {}
 
     Status validateHost(const HostAndPort& remoteHost,
+                        const BSONObj& request,
                         const RemoteCommandResponse& isMasterReply) override {
-        return _validateFunc(remoteHost, isMasterReply);
+        return _validateFunc(remoteHost, request, isMasterReply);
     }
 
     StatusWith<boost::optional<RemoteCommandRequest>> makeRequest(const HostAndPort& remoteHost) {