@Override
    public Set<String> getAndListen(URL url, MappingListener mappingListener) {
        String serviceInterface = url.getServiceInterface();
        // randomly pick one metadata report is ok for it's guaranteed all metadata report will have the same mapping
        // data.
        String registryCluster = getRegistryCluster(url);
        MetadataReport metadataReport = metadataReportInstance.getMetadataReport(registryCluster);
        if (metadataReport == null) {
            return Collections.emptySet();
        }
        return metadataReport.getServiceAppMapping(serviceInterface, mappingListener, url);
    }
@Test
    void testGetAndListen() {
        // TODO
    }