function SampleTimeSubscriber(destination, period, scheduler) {
        var _this = _super.call(this, destination) || this;
        _this.period = period;
        _this.scheduler = scheduler;
        _this.hasValue = false;
        _this.add(scheduler.schedule(dispatchNotification, period, { subscriber: _this, period: period }));
        return _this;
    }
Removes files and folders in a directory recursively.

@param {string} root
@private