https://www.zhihu.com/question/29138530
https://segmentfault.com/q/1010000002598843/a-1020000002601451
https://github.com/antlinker/go-mqtt/tree/master/
https://github.com/Terry-Mao/gopush-cluster/blob/master/README_zh.md
https://www.v2ex.com/t/92125
https://zhidao.baidu.com/question/391804230787754285.html
https://zhidao.baidu.com/question/529758921.html
https://www.baidu.com/s?wd=mqtt%20golang&pn=10&oq=mqtt%20golang&ie=utf-8&rsv_pq=b00bd1e80000b48a&rsv_t=049a64W%2BqHjPO72kCyayOa6WV7XGIsHB%2Bq5ylpCsARw0%2FBEhbKF%2BPmOJtZg&rsv_page=1