code: def _recv_flow(self, method_frame):
          '''
          Receive a flow control command from the broker
          '''
          self.channel._active = method_frame.args.read_bit()
  
          args = Writer()
          args.write_bit(self.channel.active)
          self.send_frame(MethodFrame(self.channel_id, 20, 21, args))
  
          if self._flow_control_cb is not None:
              self._flow_control_cb(f _recv_flow(self, method_frame):
          '''
          Receive a flow control command from the broker
          '''
          self.channel._active = method_frame.args.read_bit()
  
          args = Writer()
          args.write_bit(self.channel.active)
          self.send_frame(MethodFrame(self.channel_id, 20, 21, args))
  
          if self._flow_control_cb is not None:
              self._flow_control_cb()
docs: Receive a flow control command from the broker