code: function openOutputTransform(headers/*, data*/) {
    /*jshint validthis:true */
    var operation = this;
  
    var txid = headers.location.substring('/v1/transactions/'.length);
  
    if (operation.withState === true) {
      return new mlutil.Transaction(txid, operation.rawHeaders['set-cookie']);
    }
  
    return {txid: txid};
  }
docs: Provides functions to open, commit, or rollback multi-statement
  transactions. The client must have been created for a user with
  the rest-writer role.
  @namespace transactions
   @ignore