IEnumerator LoadResourceCorotine(string resName
    UnityWebRequest request=UnityWebRequest.GetAssetBundle
    yield return request.SendWebRequest();
    AssetBundle ab=request.downloadHandler as DownloadHandler).assetBundle;//将下载的内容作为ab包
    GameObject gameobject=ab.LoadAsset<GameObject>(resName)
    prefabDict.Add(resName,gameObject)

}