code: @BetaApi
    public final ListRegionBackendServicesPagedResponse listRegionBackendServices(String region) {
      ListRegionBackendServicesHttpRequest request =
          ListRegionBackendServicesHttpRequest.newBuilder().setRegion(region).build();
      return listRegionBackendServices(request);
    }
docs: Retrieves the list of regional BackendService resources available to the specified project in
  the given region.
  
  <p>Sample code:
  
  <pre><code>
  try (RegionBackendServiceClient regionBackendServiceClient = RegionBackendServiceClient.create()) {
  ProjectRegionName region = ProjectRegionName.of("[PROJECT]", "[REGION]");
  for (BackendService element : regionBackendServiceClient.listRegionBackendServices(region.toString()).iterateAll()) {
  // doThingsWith(element);
  }
  }
  </code></pre>
  
  @param region Name of the region scoping this request.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails