IEnumerator RequestAsset(string url, int version, DidFinishedDowned finished, DidFailedDowned faild)
 {
     WWW www = WWW.LoadFromCacheOrDownload (url, version);
     //		while(!www.isDone)
     //		{
     //			yield return 0;
     //		}
     if (www.error != null) {
         faild (www.error);
         yield break;
     }
     yield return www;
     finished (www.assetBundle);
 }
 // Use this for initialization
 //    string assetUrl = "file:///" + Application.dataPath + "/PackedAssets/PackedAssets";
 //    void OnGUI ()
 //    {
 //        if (GUILayout.Button ("下载资源")) {
 //
 //
 //        }
 //    }
 void DownloadAsset(string url, int version, DidFinishedDowned finished, DidFailedDowned faild)
 {
     //		StartCoroutine (url, version, finished, faild);
 }