WWW.LoadFromCacheOrDownload使用统一在Android手机上的增强现实应用程序中不起作用

I am trying to build an augmented reality app and in that app i want some prefabs to load dynamically. So that with some 3d model prefabs on unity store i created myasset.unity3d . I am using WWW.LoadFromCacheOrDownload to download that unity3d file and using it.I am trying to build an augmented reality app a