code: 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();
  }
docs: /*-------------------------------------------- 
  Batch (extends RecordStream implements Sendable)
  
  @protected
  @class Bulk~Batch
  @extends {RecordStream}
  @implements {Promise.<Array.<RecordResult>>}
  @param {Bulk~Job} job - Bulk job object
  @param {String} [batchId] - Batch ID (if already available)