UTextureCube->UTexture->UStreamableRenderAsset,IInterface_AssetUserData
FSkyTextureCubeResource->FTexture,FDeferredCleanupInterface FTexture->FRenderResource
typedef TRefCountPtr<FRHITextureCube> FTextureCubeRHIRef;
FRHITextureCube->FRHITexture->FRHIResource