@Override
  public void shutdownNow() {
    backgroundResources.shutdownNow();
  }
Constructs an instance of GrpcVpcAccessServiceStub, 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-vpcaccess/google-cloud-vpcaccess/src/main/java/com/google/cloud/vpcaccess/v1/stub/GrpcVpcAccessServiceStub.java