code: def flush_incoming(self):
          
          while True:
              try:
                  stanza_obj = self._incoming_queue.get_nowait()
              except asyncio.QueueEmpty:
                  break
              self._process_incoming(None, stanza_obj)
docs: Flush all incoming queues to the respective processing methods. The
          handlers are called as usual, thus it may require at least one
          iteration through the asyncio event loop before effects can be seen.
  
          The incoming queues are empty after a call to this method.
  
          It is legal (but pretty useless) to call this method while the stream
          is :attr:`running`.