docs: void onReadingThreadFinished(WebSocketFrame closeFrame)
      {
          synchronized (mThreadsLock)
          {
              mReadingThreadFinished = true;
              mServerCloseFrame = closeFrame;
  
              if (mWritingThreadFinished == false)
              {
                  // Wait for the writing thread to finish.
                  return;
              }
          }
  
          // Both the reading thread and the writing thread have finished.
          onThreadsFinished();
      }