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diff --git a/src/mongo/db/s/resharding/resharding_oplog_fetcher.h b/src/mongo/db/s/resharding/resharding_oplog_fetcher.h
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+/**
+ *    Copyright (C) 2020-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 "mongo/base/status_with.h"
+#include "mongo/client/dbclient_base.h"
+#include "mongo/db/namespace_string.h"
+#include "mongo/db/operation_context.h"
+#include "mongo/db/pipeline/expression_context.h"
+#include "mongo/db/s/resharding/donor_oplog_id_gen.h"
+#include "mongo/s/shard_id.h"
+#include "mongo/util/uuid.h"
+
+namespace mongo {
+class ReshardingOplogFetcher {
+public:
+    /**
+     * Issues an aggregation to `DBClientBase`s starting at `startAfter` and copies the entries
+     * relevant to `recipientShard` into `toWriteInto`. Control is returned when the aggregation
+     * cursor is exhausted.
+     *
+     * Returns an identifier for the last oplog-ish document written to `toWriteInto`.
+     *
+     * This method throws.
+     *
+     * TODO SERVER-51245 Replace `DBClientBase` with a `Shard`. Right now `Shard` does not do things
+     * like perform aggregate commands nor does it expose a cursor/stream interface. However, using
+     * a `Shard` object will provide critical behavior such as advancing logical clock values on a
+     * response and targetting a node to send the aggregation command to.
+     */
+    ReshardingDonorOplogId iterate(OperationContext* opCtx,
+                                   DBClientBase* conn,
+                                   boost::intrusive_ptr<ExpressionContext> expCtx,
+                                   ReshardingDonorOplogId startAfter,
+                                   UUID collUUID,
+                                   const ShardId& recipientShard,
+                                   bool doesDonorOwnMinKeyChunk,
+                                   NamespaceString toWriteInto);
+
+private:
+};
+}  // namespace mongo