code: @BetaApi
    public final ListRegionDiskTypesPagedResponse listRegionDiskTypes(ProjectRegionName region) {
      ListRegionDiskTypesHttpRequest request =
          ListRegionDiskTypesHttpRequest.newBuilder()
              .setRegion(region == null ? null : region.toString())
              .build();
      return listRegionDiskTypes(request);
    }
docs: Retrieves a list of regional disk types available to the specified project.
  
  <p>Sample code:
  
  <pre><code>
  try (RegionDiskTypeClient regionDiskTypeClient = RegionDiskTypeClient.create()) {
  ProjectRegionName region = ProjectRegionName.of("[PROJECT]", "[REGION]");
  for (DiskType element : regionDiskTypeClient.listRegionDiskTypes(region).iterateAll()) {
  // doThingsWith(element);
  }
  }
  </code></pre>
  
  @param region The name of the region for this request.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails