When copying, create all progress bars in advance

[mtrmac]

Per https://github.com/containers/image/pull/1530#pullrequestreview-954602860 :

Something I would love to see in the UX is to draw all progress bars before pulling. Currently, a bar is drawn the moment we start pulling the blob.

It would be nice to have them all drawn before.

Considerations:

• Do we do this just for layers (which should be easy), or including the config (currently a separate progress pool)?
• Would we want to differentiate “not started working on this blob yet” vs. “started and made no progress” somehow? Is that possible?

[vrothberg]

Thanks for filing the issue!

Do we do this just for layers (which should be easy), or including the config (currently a separate progress pool)?

Starting with layers would already be a very nice improvement.

Would we want to differentiate “not started working on this blob yet” vs. “started and made no progress” somehow? Is that possible?

That's an interesting idea. I think it would be good have a queued status initially and only draw the bar when the pulling for a given blob has commenced.