code: func (t Type) defaultFlags() byte {
  	switch t {
  	case CONNECT:
  		return 0
  	case CONNACK:
  		return 0
  	case PUBACK:
  		return 0
  	case PUBREC:
  		return 0
  	case PUBREL:
  		return 2 // 00000010
  	case PUBCOMP:
  		return 0
  	case SUBSCRIBE:
  		return 2 // 00000010
  	case SUBACK:
  		return 0
  	case UNSUBSCRIBE:
  		return 2 // 00000010
  	case UNSUBACK:
  		return 0
  	case PINGREQ:
  		return 0
  	case PINGRESP:
  		return 0
  	case DISCONNECT:
  		return 0
  	}
  
  	return 0
  }
docs: // DefaultFlags returns the default flag values for the packet type, as defined
  // by the MQTT spec, except for PUBLISH.