@Override
    public void refresh() {
        if (MapUtils.isEmpty(handlerMap)) {
            return;
        }
        LOG.info("start refresh metadata");
        handlerMap.forEach((k, v) -> v.refresh());
    }
Instantiates a new Common meta data subscriber.

@param metaDataHandlerList the plugin data handler list
shenyu-plugin/shenyu-plugin-base/src/main/java/org/apache/shenyu/plugin/base/cache/CommonMetaDataSubscriber.java