docs: def flush(self):
          """ Flush message queue if there's an active connection running """
          self._pending_flush = False
  
          if self.handler is None:
              return
  
          if self.send_queue.is_empty():
              return
  
          self.handler.send_pack('a[%s]' % self.send_queue.get())
          self.send_queue.clear()