public TpuStub getStub() {
    return stub;
  }
Constructs an instance of TpuClient, 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-tpu/google-cloud-tpu/src/main/java/com/google/cloud/tpu/v2/TpuClient.java