xitrum.handler.inbound
See https://github.com/netty/netty/blob/master/example/src/main/java/io/netty/example/http/websocketx/server/WebSocketServerHandler.java
See https://github.com/netty/netty/blob/master/example/src/main/java/io/netty/example/http/websocketx/server/WebSocketServerHandler.java