I followed this code to let user download files to cache to display them offline: https://serviceworke.rs/cache-from-zip.html
It works, but with large files it can take some time so I would like to show a progress indicator while loading the zip file.
I guess it's in the fetch part that it could be done but I don't know how: https://serviceworke.rs/cache-from-zip_worker_doc.html