Comment 14 for bug 2029417

I have a small reproducer. I think it's (almost?) impossible to reproduce the race condition that leads to the closed handler: they have a pretty unique env and we had to wait more than 1 month to hit the bug again.
So I focused on forcing the same exception at the same place and I'm now working on a new fix. For the record the reproducer is here https://github.com/r00ta/maas-bugs-reproducers/tree/main/lp-2029417