Progress bar does not display until after the first item is complete

[max-sixty]

Take this example:

    with click.progressbar(length=6, label="Doing something") as bar:
        for thing in [3, 2, 1]:
            time.sleep(thing)
            bar.update(thing)

This shows nothing until three seconds, at which point it shows:

Doing something  [##################------------------]   50%  00:00:03

Would it be reasonable for it to display a 0% at first?
This is mostly an issue with a small number of items which take a long time.

[davidism]

Duplicate of #1353.

[max-sixty]

I saw that issue – fine if you prefer to group them. It's not necessarily the same issue though: would be possible to display the last item and start showing from the 0th item.

[davidism]

This was introduced in #487. I just ran into the same confusion when fixing the tests for #1353/#1354, the first line of progress wasn't shown and it wasn't clear why. Reading #487, I'm not convinced by the reasoning, if you have a fast machine or fast process, it doesn't hurt to output the progress bar. I'm going to revert that.

Maybe it would make sense to somehow hide the progress bar if all iterations finish quickly, but otherwise you end up in this weird situation where the bar displays late because the first iteration is always "fast". I don't see a simple way to implement that though, and in general want to avoid adding complexity to Click's progress bar at this point.