@Override
  public UnaryCallable<PurgeProductsRequest, Operation> purgeProductsCallable() {
    return purgeProductsCallable;
  }
Constructs an instance of HttpJsonProductSearchStub, 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/HttpJsonProductSearchStub.java