docs: function (opts) {
              var queryStream = this.fetchRows(this.selectSql, merge(opts || {}, {stream: true})), rowCb, ret;
              if ((rowCb = this.rowCb)) {
                  ret = new TransformStream({objectMode: true});
                  ret._transform = function (data, encoding, done) {
                      when(rowCb(data)).chain(function (data) {
                          ret.push(data);
                          done();
                      }, done);
                  };
                  pipeAll(queryStream, ret);
              } else {
                  ret = queryStream;
              }
              return ret;
          }