How do you use Resources.LoadAsync with a multiple frame sprite?

I am trying to load all my sprites asynchronously and it works for single frame sprites, but if the sprite is setup to Sprite Mode: Multiple, only the first frame is loaded. All the answers I've found for loading multiple-frame sprites is to use Resources.LoadAll, which is what I was doing before. As there is no " Resources.LoadAllAsync" command, how do you load multiple frame sprites asynchronously?

 resourceRequest = Resources.LoadAsync<Sprite>(loadPath);//path to multiple sprite mode sprite
 while (!resourceRequest.isDone)
 {
     yield return 0;
 }
 sprite = (Sprite)resourceRequest.asset;//contains frame 0