code: def qos(self, prefetch_size=0, prefetch_count=0, is_global=False):
          '''
          Set QoS on this channel.
          '''
          args = Writer()
          args.write_long(prefetch_size).\
              write_short(prefetch_count).\
              write_bit(is_global)
          self.send_frame(MethodFrame(self.channel_id, 60, 10, args))
  
          self.channel.add_synchronous_cb(self._recv_qos_okf qos(self, prefetch_size=0, prefetch_count=0, is_global=False):
          '''
          Set QoS on this channel.
          '''
          args = Writer()
          args.write_long(prefetch_size).\
              write_short(prefetch_count).\
              write_bit(is_global)
          self.send_frame(MethodFrame(self.channel_id, 60, 10, args))
  
          self.channel.add_synchronous_cb(self._recv_qos_ok)
docs: Set QoS on this channel.