code: func (e *Enqueuer) EnqueueUnique(jobName string, args map[string]interface{}) (*Job, error) {
  	return e.EnqueueUniqueByKey(jobName, args, nil)
  }
docs: // EnqueueUnique enqueues a job unless a job is already enqueued with the same name and arguments.
  // The already-enqueued job can be in the normal work queue or in the scheduled job queue.
  // Once a worker begins processing a job, another job with the same name and arguments can be enqueued again.
  // Any failed jobs in the retry queue or dead queue don't count against the uniqueness -- so if a job fails and is retried, two unique jobs with the same name and arguments can be enqueued at once.
  // In order to add robustness to the system, jobs are only unique for 24 hours after they're enqueued. This is mostly relevant for scheduled jobs.
  // EnqueueUnique returns the job if it was enqueued and nil if it wasn't