说明：  MQTT协议 3.1.1中文版 MQTT是一个客户端服务端架构的发布/订阅模式的消息传输协议。它的设计思想是轻巧、开放、简单、规范，因此易于实现。这些特点使得它对很多场景来说都是很好的选择，包括受限的环境如机器与机器的通信（M2M）以及物联网环境（IoT），这些场景要求很小的代码封装或者网络带宽非常昂贵。
(MQTT is a messaging protocol in publish/subscribe mode of client server architecture. Its design idea is lightweight, open, simple and standardized, so it is easy to implement. These features make it a good choice for many scenarios, including limited environments such as machine-to-machine communication (M2M) and Internet of Things (IoT), which require very small code encapsulation or very expensive network bandwidth)