@NonNull
        @Override
        public List<String> getSubProtocols() {
            return this.subProtocols;
        }
Instantiates a new shenyu web socket handler.

@param url       the url
@param client    the client
@param headers   the headers
@param protocols the protocols
shenyu-plugin/shenyu-plugin-proxy/shenyu-plugin-websocket/src/main/java/org/apache/shenyu/plugin/websocket/WebSocketPlugin.java