code: def Recv(self):
      
      size = struct.unpack(_STRUCT_FMT, self._ReadN(_STRUCT_LEN))[0]
      if size > MAX_SIZE:
        raise ProtocolError("Expected size to be at most %d, got %d" % (MAX_SIZE,
                                                                        size))
      with self._read_lock:
        buf = self._ReadN(size)
        self._ReadMagic()
  
      res = common_pb2.Message()
      res.ParseFromString(buf)
  
      return res, len(buf)
docs: Accept a message from Fleetspeak.
  
      Returns:
        A tuple (common_pb2.Message, size of the message in bytes).
      Raises:
        ProtocolError: If we receive unexpected data from Fleetspeak.