_pushToQueue(batch) {
    this.queue.push({
      data: batch,
      owner: this,
    }, (error, result) => {
      if (error) {
        return this._notify(error, error.response.body, batch);
      }
      return this._notify(null, result.body, batch);
    });
  }
Takes a batch and pushes it to the queue, handling the result as well.

@param {Array} batch A batch to send to the queue.