docs: function scheduleTick(rootContext) {
      if (rootContext.clean == _CLEAN_PROMISE) {
          var res_1;
          rootContext.clean = new Promise(function (r) { return res_1 = r; });
          rootContext.scheduler(function () {
              tickRootContext(rootContext);
              res_1(null);
              rootContext.clean = _CLEAN_PROMISE;
          });
      }
  }