code: function CPUJob(miner, attempt) {
    this.miner = miner;
    this.attempt = attempt;
    this.destroyed = false;
    this.committed = false;
    this.start = util.now();
    this.nonce1 = 0;
    this.nonce2 = 0;
    this.refresh();
  }
docs: Mining Job
  @constructor
  @ignore
  @param {CPUMiner} miner
  @param {BlockTemplate} attempt