When evaluating this form

        (dolist-with-progress-reporter (i (number-sequence 1 4))
            "Doing stuff"
          (sleep-for 1))

I would expect to get the messages

Doing stuff...
Doing stuff...25%
Doing stuff...50%
Doing stuff...75%
Doing stuff...Done

each update after one argument of the list has been handled. Instead, it
seems I get

Doing stuff...
Doing stuff...33%
Doing stuff...66%
Doing stuff...100%
Doing stuff...Done

This confuses me, because after "processing" one out of four elements, I
wouldn't expect the message to say I already finished a third. And on
the other side, I am still not done after reaching 100%, and in this
case, am still waiting for the last element to be processed.

I am not sure if this is intentional, but in case it is no, the
following patch should fix it: