http://netty.io/
http://socket.io/
https://github.com/StackExchange/NetGain
https://github.com/SignalR/SignalR
https://github.com/uWebSockets
https://github.com/statianzo/Fleck
https://github.com/sta/websocket-sharp
https://github.com/vtortola/WebSocketListener
https://www.oschina.net/translate/websocket-libraries-comparison-2