message: fix: invalid memory access in MediaManager when stopping Core
  Since ThreadDelegate calls set_delegate() inside its destructor,
  we need to delete ThreadDelegate first, then Thread.
  This is detected by valgrind.
diff: @@ -48,8 +48,8 @@ StreamerAdapter::~StreamerAdapter() {
  streamer_->Close();
  }
  thread_->join();
  - threads::DeleteThread(thread_);
  delete streamer_;
  + threads::DeleteThread(thread_);
  }
  void StreamerAdapter::StartActivity(int32_t application_key) {
  