code: function WorkerJob(msg, options, callback) {
    this.msg = msg || {};
    this.options = options || {};
    this.callback = callback;
  }
docs: /*
  Worker job class.
  
  @param {Object} msg Message object.
  @param {Options} options Worker options.
  @param {Function} callback Callback which is called with an optional error
  as the first argument and the worker object as the
  second one.