Loading a very large animation file with the editor takes time very much

Loading a very large animation file with the editor takes time very much.

If you build it, it will be completed in a very short time.

Even in the editor, loading the animation file into the animation controller completes loading as soon as possible.

This happens when instantiating a timeline gaming object containing animation.
* I think that it will occur even without using the timeline.

Is there a way to finish loading early in the editor too?