dev := iot.NewDevice(cnf)
    if err := dev.Connect(); err != nil {
        logger.Log("error on connecting:", err.Error())
        return
    }
    logger.Log("msg", "connected.")
    if err := dev.SubscribePropertyMessage(onReceiveMessage); err != nil {
        logger.Log("error on subscribe property message:", err.Error())
        return
    }
    logger.Log("msg", "subscrib property message.")