@InternalApi
  public PredictionServiceClient getPredictionServiceClient() {
    return predictionClientSupplier.get();
  }
Returns the {@link PredictionServiceClient} with GRPC or REST, based on the Transport type. The
client will be instantiated when the first prediction API call is made.

@return {@link PredictionServiceClient} that send requests to the backing service through
    method calls that map to the API methods.
java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/VertexAI.java