public static String clientMessagesRegion(InternalCache cache, String ePolicy, int capacity,
      int port, String overFlowDir, boolean isDiskStore) {
    InternalRegionFactory factory =
        getRegionFactoryForClientMessagesRegion(cache, ePolicy, capacity, overFlowDir, isDiskStore);
    return createClientMessagesRegion(factory, port);
  }
create client subscription

@return client subscription name
@since GemFire 5.7
geode-core/src/main/java/org/apache/geode/internal/cache/CacheServerImpl.java