I was expecting an explanation about the initial
request.
Is there an oversight (??) or an another reason to not
have a Barrier primitive in asyncio ?
Probably because nobody working on asyncio at the time
had any experience using threading.Barrier. I know that I
have used all the other primitives, but I don't recall ever
having used Barrier. I don't think there's anything deeper
than that. You should probably just open a bpo issue
(mention this thread) and submit a PR linked there. I can't
promise to review it though. :-)