Question: how to show a loader while prefilling the page?

I couldn't find a way to show a loader while prefilling the page with images until it's scrollable. Am I just missing something or is this function not implemented?

edit: i managed to do it on my own but i guess it would still be nice if this got answered in case anybody else looks for this functionality

Start by reviewing the infinite-scroll loading and prefill behavior and the existing documentation; the issue names no files or tests. Done would be a clear documented answer explaining whether a loader is supported and how to use it, if the project can provide one.

Written by the indexing model from the issue text.