docs: async def _handle_pong(self, message):
          """
          Handles pong results, which don't come inside a ``rpc_result``
          but are still sent through a request:
  
              pong#347773c5 msg_id:long ping_id:long = Pong;
          """
          pong = message.obj
          self._log.debug('Handling pong for message %d', pong.msg_id)
          state = self._pending_state.pop(pong.msg_id, None)
          if state:
              state.future.set_result(pong)