IM参考
- https://github.com/defineYIDA/NoneIM.git
- https://github.com/wildfirechat/server
- https://mp.weixin.qq.com/s/52TcYdrYfwmd6B8AjdWtLw
- https://github.com/ryvengray/Netty-Distributed-IM
- https://zhuanlan.zhihu.com/p/401676544
- https://github.com/crossoverJie/cim
- http://www.52im.net/thread-2768-1-1.html
- https://github.com/beardlessCat/im
- https://github.com/JackJiang2011/MobileIMSDK
- https://github.com/fuzhengwei/NaiveChat
