docs: function(job, batchId) {
    Batch.super_.apply(this);
    this.sendable = true;
    this.job = job;
    this.id = batchId;
    this._bulk = job._bulk;
    this._csvStream = new RecordStream.CSVStream();
    this._csvStream.stream().pipe(this.stream());
    this._deferred = Promise.defer();
  }