Check channel state on iterate

[jakobnissen]

Before, iterate on Channel would return nothing when the channel was closed, not checking if it was closed with an error.

Closes #52974

[jakobnissen]

Okay that implementation won't work, and a real implementation will have a bunch of atomic and concurrency stuff I don't know enough about to be confident in trying, and won't be confident that I won't create hard-to-detect bugs

[vtjnash]

You could inline this implementation but skip throwing the InvalidStateException, or perhaps more easily, just delete the isopen check at the top and let take! handle everything (as it already implements everything necessary)

[jakobnissen]

Test failures appear to be spurious libgit connection issues.

I think this PR is good to go, modulo one decision: This PR's current behaviour is that iterate on a closed channel will not throw if the channel is not empty. The docs for close states that this is the case for take! and fetch, but does not mention iterate. Is this correct? Could the docs for close be expanded to mention iterate?

[jakobnissen]

Bump

[quinnj]

I like the change/fix/clean up here; I've been annoyed before that it always throws when done iterating.