@Bean
    @ConditionalOnMissingBean(EtcdDataDataChangedListener.class)
    public DataChangedListener etcdDataChangedListener(final EtcdClient etcdClient) {
        return new EtcdDataDataChangedListener(etcdClient);
    }
Config event listener data changed listener.

@param etcdClient the etcd client
@return the data changed listener
shenyu-admin-listener/shenyu-admin-listener-etcd/src/main/java/org/apache/shenyu/admin/config/EtcdSyncConfiguration.java