@Override
  public UnaryCallable<AsyncBatchAnnotateImagesRequest, Operation>
      asyncBatchAnnotateImagesCallable() {
    return asyncBatchAnnotateImagesCallable;
  }
Constructs an instance of GrpcImageAnnotatorStub, using the given settings. This is protected
so that it is easy to make a subclass, but otherwise, the static factory methods should be
preferred.
java-vision/google-cloud-vision/src/main/java/com/google/cloud/vision/v1/stub/GrpcImageAnnotatorStub.java