Add onFileStart, onFileEnd callback functions.

[chrislaurie-io]

I use file picker with multi-select, often from cloud storage. This means that there can be a long wait between when the user selected the files and when they are ready to be processed. It then appears that the app is hanging. I show a spinner, but would love to give feedback to the user, so they can see there is something happening.

I was thinking of adding callbacks on file start and on file end. Possibly even a callback, say every 200 milliseconds, to indicate progress on larger files. Then I can give good feedback to the user.

[github-actions]

This issue is stale because it has been open for 14 days with no activity.

[github-actions]

This issue was closed because it has been inactive for 14 days since being marked as stale.