[]怎么实现一个Timer的loop的delay时间越来越短?

		public function LayaAirDemo()

		{

			Laya.init(Browser.width,Browser.height);

			Laya.stage.bgColor="#EEFFCC";

			sp=new Sprite();

			sp.graphics.drawRect(0,0,200,200,"#FF0000");

			Laya.stage.addChild(sp);

			

			Laya.timer.loop(delay,this,onLoop);

		}

		

		private function onLoop():void

		{

			delay-=50;

			sp.x+=20;

			Laya.timer.clear(this,onLoop);

			Laya.timer.loop(delay,this,onLoop);

		}