Extracts ssrc based feedback tracking from feedback adapter.
This prepares for moving TransportFeedbackAdapter to TaskQueue.
Bug: webrtc:9883
Change-Id: Ib333f6a6837ff6dd8b10813e8953e4d8cd5d8633
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/162040
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30076}
diff --git a/call/rtp_transport_controller_send.cc b/call/rtp_transport_controller_send.cc
index bd8e2d0..00a3e0b 100644
--- a/call/rtp_transport_controller_send.cc
+++ b/call/rtp_transport_controller_send.cc
@@ -228,7 +228,7 @@
}
StreamFeedbackProvider*
RtpTransportControllerSend::GetStreamFeedbackProvider() {
- return &transport_feedback_adapter_;
+ return &feedback_demuxer_;
}
void RtpTransportControllerSend::RegisterTargetTransferRateObserver(
diff --git a/call/rtp_transport_controller_send.h b/call/rtp_transport_controller_send.h
index b5a53d7..4e9ff4d 100644
--- a/call/rtp_transport_controller_send.h
+++ b/call/rtp_transport_controller_send.h
@@ -24,6 +24,7 @@
#include "call/rtp_video_sender.h"
#include "modules/congestion_controller/rtp/control_handler.h"
#include "modules/congestion_controller/rtp/transport_feedback_adapter.h"
+#include "modules/congestion_controller/rtp/transport_feedback_demuxer.h"
#include "modules/pacing/paced_sender.h"
#include "modules/pacing/packet_router.h"
#include "modules/pacing/rtp_packet_pacer.h"
@@ -149,6 +150,7 @@
std::unique_ptr<TaskQueuePacedSender> task_queue_pacer_;
TargetTransferRateObserver* observer_ RTC_GUARDED_BY(task_queue_);
+ TransportFeedbackDemuxer feedback_demuxer_;
// TODO(srte): Move all access to feedback adapter to task queue.
TransportFeedbackAdapter transport_feedback_adapter_;
diff --git a/modules/congestion_controller/rtp/BUILD.gn b/modules/congestion_controller/rtp/BUILD.gn
index 36a9b25..38a4bf1 100644
--- a/modules/congestion_controller/rtp/BUILD.gn
+++ b/modules/congestion_controller/rtp/BUILD.gn
@@ -45,6 +45,8 @@
sources = [
"transport_feedback_adapter.cc",
"transport_feedback_adapter.h",
+ "transport_feedback_demuxer.cc",
+ "transport_feedback_demuxer.h",
]
deps = [
@@ -69,6 +71,7 @@
sources = [
"transport_feedback_adapter_unittest.cc",
+ "transport_feedback_demuxer_unittest.cc",
]
deps = [
":transport_feedback",
diff --git a/modules/congestion_controller/rtp/transport_feedback_adapter.cc b/modules/congestion_controller/rtp/transport_feedback_adapter.cc
index b070b0e..8783b73 100644
--- a/modules/congestion_controller/rtp/transport_feedback_adapter.cc
+++ b/modules/congestion_controller/rtp/transport_feedback_adapter.cc
@@ -66,30 +66,6 @@
TransportFeedbackAdapter::TransportFeedbackAdapter() = default;
-TransportFeedbackAdapter::~TransportFeedbackAdapter() {
- RTC_DCHECK(observers_.empty());
-}
-
-void TransportFeedbackAdapter::RegisterStreamFeedbackObserver(
- std::vector<uint32_t> ssrcs,
- StreamFeedbackObserver* observer) {
- rtc::CritScope cs(&observers_lock_);
- RTC_DCHECK(observer);
- RTC_DCHECK(absl::c_find_if(observers_, [=](const auto& pair) {
- return pair.second == observer;
- }) == observers_.end());
- observers_.push_back({ssrcs, observer});
-}
-
-void TransportFeedbackAdapter::DeRegisterStreamFeedbackObserver(
- StreamFeedbackObserver* observer) {
- rtc::CritScope cs(&observers_lock_);
- RTC_DCHECK(observer);
- const auto it = absl::c_find_if(
- observers_, [=](const auto& pair) { return pair.second == observer; });
- RTC_DCHECK(it != observers_.end());
- observers_.erase(it);
-}
void TransportFeedbackAdapter::AddPacket(const RtpPacketSendInfo& packet_info,
size_t overhead_bytes,
@@ -104,10 +80,6 @@
packet.local_net_id = local_net_id_;
packet.remote_net_id = remote_net_id_;
packet.sent.pacing_info = packet_info.pacing_info;
- if (packet_info.has_rtp_sequence_number) {
- packet.ssrc = packet_info.ssrc;
- packet.rtp_sequence_number = packet_info.rtp_sequence_number;
- }
while (!history_.empty() &&
creation_time - history_.begin()->second.creation_time >
@@ -168,32 +140,25 @@
RTC_LOG(LS_INFO) << "Empty transport feedback packet received.";
return absl::nullopt;
}
- std::vector<PacketFeedback> feedback_vector;
+
+ rtc::CritScope cs(&lock_);
TransportPacketsFeedback msg;
msg.feedback_time = feedback_receive_time;
- {
- rtc::CritScope cs(&lock_);
- msg.prior_in_flight =
- in_flight_.GetOutstandingData(local_net_id_, remote_net_id_);
- feedback_vector =
- ProcessTransportFeedbackInner(feedback, feedback_receive_time);
- if (feedback_vector.empty())
- return absl::nullopt;
- for (const PacketFeedback& fb : feedback_vector) {
- PacketResult res;
- res.sent_packet = fb.sent;
- res.receive_time = fb.receive_time;
- msg.packet_feedbacks.push_back(res);
- }
- auto it = history_.find(last_ack_seq_num_);
- if (it != history_.end()) {
- msg.first_unacked_send_time = it->second.sent.send_time;
- }
- msg.data_in_flight =
- in_flight_.GetOutstandingData(local_net_id_, remote_net_id_);
+ msg.prior_in_flight =
+ in_flight_.GetOutstandingData(local_net_id_, remote_net_id_);
+ msg.packet_feedbacks =
+ ProcessTransportFeedbackInner(feedback, feedback_receive_time);
+ if (msg.packet_feedbacks.empty())
+ return absl::nullopt;
+
+ auto it = history_.find(last_ack_seq_num_);
+ if (it != history_.end()) {
+ msg.first_unacked_send_time = it->second.sent.send_time;
}
- SignalObservers(feedback_vector);
+ msg.data_in_flight =
+ in_flight_.GetOutstandingData(local_net_id_, remote_net_id_);
+
return msg;
}
@@ -209,7 +174,7 @@
return in_flight_.GetOutstandingData(local_net_id_, remote_net_id_);
}
-std::vector<PacketFeedback>
+std::vector<PacketResult>
TransportFeedbackAdapter::ProcessTransportFeedbackInner(
const rtcp::TransportFeedback& feedback,
Timestamp feedback_time) {
@@ -225,8 +190,8 @@
}
last_timestamp_ = feedback.GetBaseTime();
- std::vector<PacketFeedback> packet_feedback_vector;
- packet_feedback_vector.reserve(feedback.GetPacketStatusCount());
+ std::vector<PacketResult> packet_result_vector;
+ packet_result_vector.reserve(feedback.GetPacketStatusCount());
size_t failed_lookups = 0;
size_t ignored = 0;
@@ -269,7 +234,10 @@
}
if (packet_feedback.local_net_id == local_net_id_ &&
packet_feedback.remote_net_id == remote_net_id_) {
- packet_feedback_vector.push_back(packet_feedback);
+ PacketResult result;
+ result.sent_packet = packet_feedback.sent;
+ result.receive_time = packet_feedback.receive_time;
+ packet_result_vector.push_back(result);
} else {
++ignored;
}
@@ -285,27 +253,7 @@
<< " packets because they were sent on a different route.";
}
- return packet_feedback_vector;
-}
-
-void TransportFeedbackAdapter::SignalObservers(
- const std::vector<PacketFeedback>& feedback_vector) {
- rtc::CritScope cs(&observers_lock_);
- for (auto& observer : observers_) {
- std::vector<StreamFeedbackObserver::StreamPacketInfo> selected_feedback;
- for (const auto& packet : feedback_vector) {
- if (packet.ssrc && absl::c_count(observer.first, *packet.ssrc) > 0) {
- StreamFeedbackObserver::StreamPacketInfo packet_info;
- packet_info.ssrc = *packet.ssrc;
- packet_info.rtp_sequence_number = packet.rtp_sequence_number;
- packet_info.received = packet.receive_time.IsFinite();
- selected_feedback.push_back(packet_info);
- }
- }
- if (!selected_feedback.empty()) {
- observer.second->OnPacketFeedbackVector(std::move(selected_feedback));
- }
- }
+ return packet_result_vector;
}
} // namespace webrtc
diff --git a/modules/congestion_controller/rtp/transport_feedback_adapter.h b/modules/congestion_controller/rtp/transport_feedback_adapter.h
index 699c6ed..b6bed96 100644
--- a/modules/congestion_controller/rtp/transport_feedback_adapter.h
+++ b/modules/congestion_controller/rtp/transport_feedback_adapter.h
@@ -38,9 +38,6 @@
// The network route ids that this packet is associated with.
uint16_t local_net_id = 0;
uint16_t remote_net_id = 0;
- // The SSRC and RTP sequence number of the packet this feedback refers to.
- absl::optional<uint32_t> ssrc;
- uint16_t rtp_sequence_number = 0;
};
class InFlightBytesTracker {
@@ -55,16 +52,9 @@
std::map<RemoteAndLocalNetworkId, DataSize> in_flight_data_;
};
-class TransportFeedbackAdapter : public StreamFeedbackProvider {
+class TransportFeedbackAdapter {
public:
TransportFeedbackAdapter();
- virtual ~TransportFeedbackAdapter();
-
- void RegisterStreamFeedbackObserver(
- std::vector<uint32_t> ssrcs,
- StreamFeedbackObserver* observer) override;
- void DeRegisterStreamFeedbackObserver(
- StreamFeedbackObserver* observer) override;
void AddPacket(const RtpPacketSendInfo& packet_info,
size_t overhead_bytes,
@@ -83,15 +73,10 @@
private:
enum class SendTimeHistoryStatus { kNotAdded, kOk, kDuplicate };
- void OnTransportFeedback(const rtcp::TransportFeedback& feedback);
-
- std::vector<PacketFeedback> ProcessTransportFeedbackInner(
+ std::vector<PacketResult> ProcessTransportFeedbackInner(
const rtcp::TransportFeedback& feedback,
Timestamp feedback_time) RTC_RUN_ON(&lock_);
- void SignalObservers(
- const std::vector<PacketFeedback>& packet_feedback_vector);
-
rtc::CriticalSection lock_;
DataSize pending_untracked_size_ RTC_GUARDED_BY(&lock_) = DataSize::Zero();
Timestamp last_send_time_ RTC_GUARDED_BY(&lock_) = Timestamp::MinusInfinity();
@@ -110,13 +95,6 @@
uint16_t local_net_id_ RTC_GUARDED_BY(&lock_) = 0;
uint16_t remote_net_id_ RTC_GUARDED_BY(&lock_) = 0;
-
- rtc::CriticalSection observers_lock_;
- // Maps a set of ssrcs to corresponding observer. Vectors are used rather than
- // set/map to ensure that the processing order is consistent independently of
- // the randomized ssrcs.
- std::vector<std::pair<std::vector<uint32_t>, StreamFeedbackObserver*>>
- observers_ RTC_GUARDED_BY(&observers_lock_);
};
} // namespace webrtc
diff --git a/modules/congestion_controller/rtp/transport_feedback_adapter_unittest.cc b/modules/congestion_controller/rtp/transport_feedback_adapter_unittest.cc
index e03bcc3..a95f866 100644
--- a/modules/congestion_controller/rtp/transport_feedback_adapter_unittest.cc
+++ b/modules/congestion_controller/rtp/transport_feedback_adapter_unittest.cc
@@ -126,58 +126,6 @@
std::unique_ptr<TransportFeedbackAdapter> adapter_;
};
-TEST_F(TransportFeedbackAdapterTest, ObserverSanity) {
- MockStreamFeedbackObserver mock;
- adapter_->RegisterStreamFeedbackObserver({kSsrc}, &mock);
-
- const std::vector<PacketResult> packets = {
- CreatePacket(100, 200, 0, 1000, kPacingInfo0),
- CreatePacket(110, 210, 1, 2000, kPacingInfo0),
- CreatePacket(120, 220, 2, 3000, kPacingInfo0)};
-
- rtcp::TransportFeedback feedback;
- feedback.SetBase(packets[0].sent_packet.sequence_number,
- packets[0].receive_time.us());
-
- for (const auto& packet : packets) {
- OnSentPacket(packet);
- EXPECT_TRUE(feedback.AddReceivedPacket(packet.sent_packet.sequence_number,
- packet.receive_time.us()));
- }
-
- EXPECT_CALL(mock, OnPacketFeedbackVector(_)).Times(1);
- adapter_->ProcessTransportFeedback(feedback, clock_.CurrentTime());
-
- adapter_->DeRegisterStreamFeedbackObserver(&mock);
-
- auto new_packet = CreatePacket(130, 230, 3, 4000, kPacingInfo0);
- OnSentPacket(new_packet);
-
- rtcp::TransportFeedback second_feedback;
- second_feedback.SetBase(new_packet.sent_packet.sequence_number,
- new_packet.receive_time.us());
- EXPECT_TRUE(second_feedback.AddReceivedPacket(
- new_packet.sent_packet.sequence_number, new_packet.receive_time.us()));
- EXPECT_CALL(mock, OnPacketFeedbackVector(_)).Times(0);
- adapter_->ProcessTransportFeedback(second_feedback, clock_.CurrentTime());
-}
-
-#if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
-TEST_F(TransportFeedbackAdapterTest, ObserverDoubleRegistrationDeathTest) {
- MockStreamFeedbackObserver mock;
- adapter_->RegisterStreamFeedbackObserver({0}, &mock);
- EXPECT_DEATH(adapter_->RegisterStreamFeedbackObserver({0}, &mock), "");
- adapter_->DeRegisterStreamFeedbackObserver(&mock);
-}
-
-TEST_F(TransportFeedbackAdapterTest, ObserverMissingDeRegistrationDeathTest) {
- MockStreamFeedbackObserver mock;
- adapter_->RegisterStreamFeedbackObserver({0}, &mock);
- EXPECT_DEATH(adapter_.reset(), "");
- adapter_->DeRegisterStreamFeedbackObserver(&mock);
-}
-#endif
-
TEST_F(TransportFeedbackAdapterTest, AdaptsFeedbackAndPopulatesSendTimes) {
std::vector<PacketResult> packets;
packets.push_back(CreatePacket(100, 200, 0, 1500, kPacingInfo0));
diff --git a/modules/congestion_controller/rtp/transport_feedback_demuxer.cc b/modules/congestion_controller/rtp/transport_feedback_demuxer.cc
new file mode 100644
index 0000000..c7893d7
--- /dev/null
+++ b/modules/congestion_controller/rtp/transport_feedback_demuxer.cc
@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+#include "modules/congestion_controller/rtp/transport_feedback_demuxer.h"
+#include "absl/algorithm/container.h"
+#include "modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
+
+namespace webrtc {
+namespace {
+static const size_t kMaxPacketsInHistory = 5000;
+}
+void TransportFeedbackDemuxer::RegisterStreamFeedbackObserver(
+ std::vector<uint32_t> ssrcs,
+ StreamFeedbackObserver* observer) {
+ rtc::CritScope cs(&observers_lock_);
+ RTC_DCHECK(observer);
+ RTC_DCHECK(absl::c_find_if(observers_, [=](const auto& pair) {
+ return pair.second == observer;
+ }) == observers_.end());
+ observers_.push_back({ssrcs, observer});
+}
+
+void TransportFeedbackDemuxer::DeRegisterStreamFeedbackObserver(
+ StreamFeedbackObserver* observer) {
+ rtc::CritScope cs(&observers_lock_);
+ RTC_DCHECK(observer);
+ const auto it = absl::c_find_if(
+ observers_, [=](const auto& pair) { return pair.second == observer; });
+ RTC_DCHECK(it != observers_.end());
+ observers_.erase(it);
+}
+
+void TransportFeedbackDemuxer::AddPacket(const RtpPacketSendInfo& packet_info) {
+ rtc::CritScope cs(&lock_);
+ if (packet_info.has_rtp_sequence_number && packet_info.ssrc != 0) {
+ StreamFeedbackObserver::StreamPacketInfo info;
+ info.ssrc = packet_info.ssrc;
+ info.rtp_sequence_number = packet_info.rtp_sequence_number;
+ info.received = false;
+ history_.insert(
+ {seq_num_unwrapper_.Unwrap(packet_info.transport_sequence_number),
+ info});
+ }
+ while (history_.size() > kMaxPacketsInHistory) {
+ history_.erase(history_.begin());
+ }
+}
+
+void TransportFeedbackDemuxer::OnTransportFeedback(
+ const rtcp::TransportFeedback& feedback) {
+ std::vector<StreamFeedbackObserver::StreamPacketInfo> stream_feedbacks;
+ {
+ rtc::CritScope cs(&lock_);
+ for (const auto& packet : feedback.GetAllPackets()) {
+ int64_t seq_num =
+ seq_num_unwrapper_.UnwrapWithoutUpdate(packet.sequence_number());
+ auto it = history_.find(seq_num);
+ if (it != history_.end()) {
+ auto packet_info = it->second;
+ packet_info.received = packet.received();
+ stream_feedbacks.push_back(packet_info);
+ if (packet.received())
+ history_.erase(it);
+ }
+ }
+ }
+
+ rtc::CritScope cs(&observers_lock_);
+ for (auto& observer : observers_) {
+ std::vector<StreamFeedbackObserver::StreamPacketInfo> selected_feedback;
+ for (const auto& packet_info : stream_feedbacks) {
+ if (absl::c_count(observer.first, packet_info.ssrc) > 0) {
+ selected_feedback.push_back(packet_info);
+ }
+ }
+ if (!selected_feedback.empty()) {
+ observer.second->OnPacketFeedbackVector(std::move(selected_feedback));
+ }
+ }
+}
+
+} // namespace webrtc
diff --git a/modules/congestion_controller/rtp/transport_feedback_demuxer.h b/modules/congestion_controller/rtp/transport_feedback_demuxer.h
new file mode 100644
index 0000000..bcd25d5
--- /dev/null
+++ b/modules/congestion_controller/rtp/transport_feedback_demuxer.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef MODULES_CONGESTION_CONTROLLER_RTP_TRANSPORT_FEEDBACK_DEMUXER_H_
+#define MODULES_CONGESTION_CONTROLLER_RTP_TRANSPORT_FEEDBACK_DEMUXER_H_
+
+#include <map>
+#include <utility>
+#include <vector>
+
+#include "modules/include/module_common_types_public.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "rtc_base/critical_section.h"
+
+namespace webrtc {
+
+class TransportFeedbackDemuxer : public StreamFeedbackProvider {
+ public:
+ // Implements StreamFeedbackProvider interface
+ void RegisterStreamFeedbackObserver(
+ std::vector<uint32_t> ssrcs,
+ StreamFeedbackObserver* observer) override;
+ void DeRegisterStreamFeedbackObserver(
+ StreamFeedbackObserver* observer) override;
+ void AddPacket(const RtpPacketSendInfo& packet_info);
+ void OnTransportFeedback(const rtcp::TransportFeedback& feedback);
+
+ private:
+ rtc::CriticalSection lock_;
+ SequenceNumberUnwrapper seq_num_unwrapper_ RTC_GUARDED_BY(&lock_);
+ std::map<int64_t, StreamFeedbackObserver::StreamPacketInfo> history_
+ RTC_GUARDED_BY(&lock_);
+
+ // Maps a set of ssrcs to corresponding observer. Vectors are used rather than
+ // set/map to ensure that the processing order is consistent independently of
+ // the randomized ssrcs.
+ rtc::CriticalSection observers_lock_;
+ std::vector<std::pair<std::vector<uint32_t>, StreamFeedbackObserver*>>
+ observers_ RTC_GUARDED_BY(&observers_lock_);
+};
+} // namespace webrtc
+
+#endif // MODULES_CONGESTION_CONTROLLER_RTP_TRANSPORT_FEEDBACK_DEMUXER_H_
diff --git a/modules/congestion_controller/rtp/transport_feedback_demuxer_unittest.cc b/modules/congestion_controller/rtp/transport_feedback_demuxer_unittest.cc
new file mode 100644
index 0000000..144e3e1
--- /dev/null
+++ b/modules/congestion_controller/rtp/transport_feedback_demuxer_unittest.cc
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+#include "modules/congestion_controller/rtp/transport_feedback_demuxer.h"
+
+#include "modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+namespace {
+
+using ::testing::_;
+static constexpr uint32_t kSsrc = 8492;
+
+class MockStreamFeedbackObserver : public webrtc::StreamFeedbackObserver {
+ public:
+ MOCK_METHOD1(OnPacketFeedbackVector,
+ void(std::vector<StreamPacketInfo> packet_feedback_vector));
+};
+
+RtpPacketSendInfo CreatePacket(uint32_t ssrc,
+ int16_t rtp_sequence_number,
+ int64_t transport_sequence_number) {
+ RtpPacketSendInfo res;
+ res.ssrc = ssrc;
+ res.transport_sequence_number = transport_sequence_number;
+ res.rtp_sequence_number = rtp_sequence_number;
+ res.has_rtp_sequence_number = true;
+ return res;
+}
+} // namespace
+TEST(TransportFeedbackDemuxerTest, ObserverSanity) {
+ TransportFeedbackDemuxer demuxer;
+ MockStreamFeedbackObserver mock;
+ demuxer.RegisterStreamFeedbackObserver({kSsrc}, &mock);
+
+ demuxer.AddPacket(CreatePacket(kSsrc, 55, 1));
+ demuxer.AddPacket(CreatePacket(kSsrc, 56, 2));
+ demuxer.AddPacket(CreatePacket(kSsrc, 57, 3));
+
+ rtcp::TransportFeedback feedback;
+ feedback.SetBase(1, 1000);
+ ASSERT_TRUE(feedback.AddReceivedPacket(1, 1000));
+ ASSERT_TRUE(feedback.AddReceivedPacket(2, 2000));
+ ASSERT_TRUE(feedback.AddReceivedPacket(3, 3000));
+
+ EXPECT_CALL(mock, OnPacketFeedbackVector(_)).Times(1);
+ demuxer.OnTransportFeedback(feedback);
+
+ demuxer.DeRegisterStreamFeedbackObserver(&mock);
+
+ demuxer.AddPacket(CreatePacket(kSsrc, 58, 4));
+ rtcp::TransportFeedback second_feedback;
+ second_feedback.SetBase(4, 4000);
+ ASSERT_TRUE(second_feedback.AddReceivedPacket(4, 4000));
+
+ EXPECT_CALL(mock, OnPacketFeedbackVector(_)).Times(0);
+ demuxer.OnTransportFeedback(second_feedback);
+}
+} // namespace webrtc