WebSocket CloseFrame, naver send back before close connection

[hangsucho]

https://tools.ietf.org/html/rfc6455#section-5.5.1

If an endpoint receives a Close frame and did not previously send a
Close frame, the endpoint MUST send a Close frame in response. (When
sending a Close frame in response, the endpoint typically echos the
status code it received.) It SHOULD do so as soon as practical. An
endpoint MAY delay sending a Close frame until its current message is
sent (for instance, if the majority of a fragmented message is
already sent, an endpoint MAY send the remaining fragments before
sending a Close frame). However, there is no guarantee that the
endpoint that has already sent a Close frame will continue to process
data.

https://github.com/mrniko/netty-socketio/blob/master/src/main/java/com/corundumstudio/socketio/transport/WebSocketTransport.java#L81

Must send back "Websocket close frame"

[hangsucho]

IE and Edge browser.

script error. developer tool. (console)

SCRIPT12030: SCRIPT12030: WebSocket Error: Network Error 12030,

[hangsucho]

https://github.com/netty/netty/blob/4.1/codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketServerHandshaker.java#L310

[hangsucho]

close issue.