  (function (schedulerProto) {

    /**
     * Schedules a periodic piece of work by dynamically discovering the scheduler's capabilities. The periodic task will be scheduled using window.setInterval for the base implementation.       
     * @param {Number} period Period for running the work periodically.
     * @param {Function} action Action to be executed.
     * @returns {Disposable} The disposable object used to cancel the scheduled recurring action (best effort).
     */        
    Scheduler.prototype.schedulePeriodic = function (period, action) {
      return this.schedulePeriodicWithState(null, period, action);
    };

    /**
     * Schedules a periodic piece of work by dynamically discovering the scheduler's capabilities. The periodic task will be scheduled using window.setInterval for the base implementation.       
     * @param {Mixed} state Initial state passed to the action upon the first iteration.
     * @param {Number} period Period for running the work periodically.
     * @param {Function} action Action to be executed, potentially updating the state.
     * @returns {Disposable} The disposable object used to cancel the scheduled recurring action (best effort).
     */
    Scheduler.prototype.schedulePeriodicWithState = function(state, period, action) {
      if (typeof root.setInterval === 'undefined') { throw new Error('Periodic scheduling not supported.'); }
      var s = state;
  
      var id = root.setInterval(function () {
        s = action(s);
      }, period);

      return disposableCreate(function () {
        root.clearInterval(id);
      });
    };

  }(Scheduler.prototype));
  