code: @Override
    public void flush() throws IOException
    {
      if (_os == null || ! _needsFlush)
        return;
  
      _needsFlush = false;
      try {
        _os.flush();
      } catch (IOException e) {
        try {
          close();
        } catch (IOException e1) {
        }
        
        throw ClientDisconnectException.create(e);
      }
    }
docs: Flushes the socket.