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diff --git a/src/mongo/transport/grpc/client_stream.h b/src/mongo/transport/grpc/client_stream.h
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+/**
+ *    Copyright (C) 2023-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    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 Server Side 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 <boost/optional.hpp>
+#include <grpcpp/grpcpp.h>
+
+#include "mongo/util/shared_buffer.h"
+
+namespace mongo::transport::grpc {
+
+/**
+ * Base class modeling a synchronous client side of a gRPC stream.
+ * See: https://grpc.github.io/grpc/cpp/classgrpc_1_1_client_reader_writer.html
+ *
+ * ClientStream::read() is thread safe with respect to ClientStream::write(), but neither method
+ * should be called concurrently with another invocation of itself on the same stream.
+ *
+ * ClientStream::finish() is thread safe with respect to ClientStream::read().
+ */
+class ClientStream {
+public:
+    virtual ~ClientStream() = default;
+
+    /**
+     * Block to read a message from the stream.
+     *
+     * Returns boost::none if the stream is closed, either cleanly or due to an underlying
+     * connection failure.
+     */
+    virtual boost::optional<SharedBuffer> read() = 0;
+
+    /**
+     * Block to write a message to the stream.
+     *
+     * Returns true if the write was successful or false if it failed due to the stream being
+     * closed, either explicitly or due to an underlying connection failure.
+     */
+    virtual bool write(ConstSharedBuffer msg) = 0;
+
+    /**
+     * Block waiting until all received messages have been read and the stream has been closed.
+     *
+     * Returns the final status of the RPC associated with this stream.
+     *
+     * This method should only be called once.
+     */
+    virtual ::grpc::Status finish() = 0;
+};
+
+}  // namespace mongo::transport::grpc