public static WebSocketSession remove(final String key) {
        log.info("remove session: {}", key);
        return SESSION_POOL.remove(key);
    }
Deleting a session will return the deleted session.
@param key key
@return the session just removed
shenyu-examples/shenyu-examples-websocket/shenyu-example-spring-native-websocket/src/main/java/org/apache/shenyu/examples/websocket/config/WsSessionManager.java