[ActionScript 3.0] AS3中Loader无法彻底卸载

我测试发现，实例化的Loader无法彻底卸载，同行有没有办法，求赐教！

import flash.display.Loader;
import flash.net.URLRequest;
import flash.events.Event;

var ldr:Loader = new Loader();
ldr.name = "ldr_0";
ldr.load(new URLRequest("D:/svn/resources/src/KioskSystem/KioskSystem_Tianjin/assets/images/weather/weather_icon/b_nothing.png"));
ldr.contentLoaderInfo.addEventListener(Event.COMPLETE,onLoaded);
this.addChild(ldr);
function onLoaded(e:Event):void
{
    ldr.unloadAndStop();
    ldr.visible = false;
    ldr = null;
    trace(ldr,(e.target as LoaderInfo).loader,(e.target as LoaderInfo).loader.name);//null [object Loader] ldr_0
    
    var temp:Loader = (e.target as LoaderInfo).loader as Loader;
    trace(temp.name,(e.target as LoaderInfo).loader.name);//ldr_0 ldr_0
    temp.visible = false;
    temp = null;
    trace((e.target as LoaderInfo).loader,(e.target as LoaderInfo).loader.name,temp);//[object Loader] ldr_0 null
}