code: private <R, A extends AsynchronouslyCreatedResource<R>> CompletableFuture<R> pollResourceAsync(
  			final Supplier<CompletableFuture<A>> resourceFutureSupplier) {
  		return pollResourceAsync(resourceFutureSupplier, new CompletableFuture<>(), 0);
  	}
docs: Creates a {@code CompletableFuture} that polls a {@code AsynchronouslyCreatedResource} until
  its {@link AsynchronouslyCreatedResource#queueStatus() QueueStatus} becomes
  {@link QueueStatus.Id#COMPLETED COMPLETED}. The future completes with the result of
  {@link AsynchronouslyCreatedResource#resource()}.
  
  @param resourceFutureSupplier The operation which polls for the
  {@code AsynchronouslyCreatedResource}.
  @param <R>                    The type of the resource.
  @param <A>                    The type of the {@code AsynchronouslyCreatedResource}.
  @return A {@code CompletableFuture} delivering the resource.