diff --git a/connections/implementation/analytics/throughput_recorder.cc b/connections/implementation/analytics/throughput_recorder.cc
index 51f4c492..62d7ac21 100644
--- a/connections/implementation/analytics/throughput_recorder.cc
+++ b/connections/implementation/analytics/throughput_recorder.cc
@@ -138,6 +138,11 @@ bool ThroughputRecorder::Stop() {
   return true;
 }
 
+void ThroughputRecorder::MarkAsSuccess() {
+  MutexLock lock(&mutex_);
+  success_ = true;
+}
+
 int ThroughputRecorder::CalculateThroughputKBps(int64_t total_byte_size,
                                                 int64_t total_millis) {
   if (total_millis > 0) {
diff --git a/connections/implementation/analytics/throughput_recorder.h b/connections/implementation/analytics/throughput_recorder.h
index d2bacd9c..e6dcdc05 100644
--- a/connections/implementation/analytics/throughput_recorder.h
+++ b/connections/implementation/analytics/throughput_recorder.h
@@ -87,7 +87,7 @@ class ThroughputRecorder {
   int64_t GetDurationMillis();
   void OnFrameSent(Medium medium, PacketMetaData& packetMetaData);
   void OnFrameReceived(Medium medium, PacketMetaData& packetMetaData);
-  void MarkAsSuccess() { success_ = true; }
+  void MarkAsSuccess();
 
  private:
   void CalculateDurationTimes(PacketMetaData packetMetaData);