Reset outgoing callback when switching media handlers

src/impl/track.cpp

@@ -182,6 +182,9 @@ bool Track::transportSend([[maybe_unused]] message_ptr message) {
 void Track::setMediaHandler(shared_ptr<MediaHandler> handler) {
 	{
 		std::unique_lock lock(mMutex);
+		if (mMediaHandler)
+			mMediaHandler->onOutgoing(nullptr);
+
 		mMediaHandler = handler;
 	}