KAFKA-18569: New consumer close may wait on unneeded FindCoordinator

[frankvicky]

JIRA: KAFKA-18569
Please refer to ticker for further details.

In short, now new consumer close may wait for a FindCoordinator unsent request to go out when closing the consumer, even after the commit/leaveGroup stages of close are done.

Committer Checklist (excluded from commit message)

• Verify design and implementation
• Verify test coverage and CI build status
• Verify documentation (including upgrade notes)

[frankvicky]

Hi @lianetm @kirktrue @chia7712
Please take a look when you have a free cycle.
Many thanks 🙇🏼

[kirktrue]

Thanks for the PR @frankvicky!

I was curious if you had a chance to look into using the pollOnClose() approach that was suggested in the Jira. If that approach works, we wouldn't need an extra ApplicationEvent.

Thanks!

[frankvicky]

Hi @kirktrue
Thanks for the review.
You're right, it's easier than having a new event. 😺
Previously I thought following CommitRequestManager could have a unified close style.