code: function PendingJob(worker, id, resolve, reject) {
    this.worker = worker;
    this.id = id;
    this.job = co.job(resolve, reject);
    this.timer = null;
  }
docs: Pending Job
  @constructor
  @ignore
  @param {Worker} worker
  @param {Number} id
  @param {Function} resolve
  @param {Function} reject