code: public static <R extends Resource<JobEntity>> Mono<Void> waitForCompletion(CloudFoundryClient cloudFoundryClient, Duration completionTimeout, R resource) {
          return waitForCompletion(cloudFoundryClient, completionTimeout, ResourceUtils.getEntity(resource));
      }
docs: Waits for a job to complete
  
  @param cloudFoundryClient the client to use to request job status
  @param completionTimeout  the amount of time to wait for the job to complete.
  @param resource           the resource representing the job
  @param <R>                the Job resource type
  @return {@code onComplete} once job has completed