In QUIC, send data is copied to streams rather than frames. Protected by FLAGS_quic_reloadable_flag…

net/quic/test_tools/simple_data_producer.h

+// Copyright (c) 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NET_QUIC_TEST_TOOLS_SIMPLE_DATA_PRODUCER_H_
+#define NET_QUIC_TEST_TOOLS_SIMPLE_DATA_PRODUCER_H_
+
+#include <unordered_map>
+
+#include "net/quic/core/quic_simple_buffer_allocator.h"
+#include "net/quic/core/quic_stream_frame_data_producer.h"
+#include "net/quic/core/quic_stream_send_buffer.h"
+
+namespace net {
+
+namespace test {
+
+// A simple data producer which copies stream data into a map from stream
+// id to send buffer.
+class SimpleDataProducer : public QuicStreamFrameDataProducer {
+ public:
+  SimpleDataProducer();
+  ~SimpleDataProducer() override;
+
+  // QuicStreamFrameDataProducer methods:
+  void SaveStreamData(QuicStreamId id,
+                      QuicIOVector iov,
+                      size_t iov_offset,
+                      QuicStreamOffset offset,
+                      QuicByteCount data_length) override;
+  bool WriteStreamData(QuicStreamId id,
+                       QuicStreamOffset offset,
+                       QuicByteCount data_length,
+                       QuicDataWriter* writer) override;
+
+ private:
+  using SendBufferMap =
+      std::unordered_map<QuicStreamId, std::unique_ptr<QuicStreamSendBuffer>>;
+
+  SendBufferMap send_buffer_map_;
+
+  SimpleBufferAllocator allocator_;
+};
+
+}  // namespace test
+
+}  // namespace net
+
+#endif  // NET_QUIC_TEST_TOOLS_SIMPLE_DATA_PRODUCER_H_