@Override
    public void close() {
        if (CollectionUtils.isNotEmpty(clients)) {
            for (ShenyuWebsocketClient client : clients) {
                if (Objects.nonNull(client)) {
                    client.close();
                }
            }
        }
        if (Objects.nonNull(timerTask)) {
            timerTask.cancel();
        }
        timer.shutdown();
    }
Instantiates a new Websocket sync cache.

@param websocketConfig the websocket config
@param shenyuConfig the shenyu config
@param pluginDataSubscriber the plugin data subscriber
@param metaDataSubscribers the meta data subscribers
@param authDataSubscribers the auth data subscribers
@param proxySelectorDataSubscribers the proxy selector data subscribers
@param discoveryUpstreamDataSubscribers the discovery upstream data subscribers
shenyu-sync-data-center/shenyu-sync-data-websocket/src/main/java/org/apache/shenyu/plugin/sync/data/websocket/WebsocketSyncDataService.java