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

@return {@link LlmUtilityServiceClient} that makes calls 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