loaderInfo.bytesTotal属性
<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/10/29/determining-the-size-of-your-flex-application/ -->
<mx:Application name="loaderInfo_bytesTotal_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white"
        applicationComplete="init();">

    <mx:Script>
        <![CDATA[
            private function init():void {
                var bTotal:uint = loaderInfo.bytesTotal;
                lbl.text = "bytesTotal: " + numberFormatter.format(bTotal);
            }
        ]]>
    </mx:Script>

    <mx:NumberFormatter id="numberFormatter" />

    <mx:Label id="lbl" />

</mx:Application>