docs: function generateNewId() {
          var i = 0;
          return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function (c) {
              var r = rng(i++) % 16 | 0,
                  v = c == 'x' ? r : r & 0x3 | 0x8;
              return v.toString(16);
          });
      }