Fix thread leak by switching to different Queue shutdown mechanism

[itamarst]

Implementing correct shutdown() would involve copying too much code, so switch to the more traditional way of indicating shutdown to a thread reading from a Queue.

❓ What kind of change does this PR introduce?

• 🐞 bug fix
• 🐣 feature
• 📋 docs update
• 📋 tests/coverage improvement
• 📋 refactoring
• 💥 other

📋 What is the related issue number (starting with #)

Resolves #769
Superseded and closes #778

❓ What is the current behavior? (You can also link to an open issue here)

The overload thread leaks in Python < 3.13.

❓ What is the new behavior (if this is a feature change)?

The thread no longer leaks.

📋 Other information:

📋 Contribution checklist:

(If you're a first-timer, check out
this guide on making great pull requests)

• I wrote descriptive pull request text above
• I think the code is well written
• I wrote good commit messages
• I have squashed related commits together after
  the changes have been approved
• Unit tests for the changes exist
• Integration tests for the changes exist (if applicable)
• I used the same coding conventions as the rest of the project
• The new code doesn't generate linter offenses
• Documentation reflects the changes
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences

[codecov]

Codecov Report

❌ Patch coverage is 93.10345% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.73%. Comparing base (22bb430) to head (8d1e5a0).
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #794      +/-   ##
==========================================
+ Coverage   79.60%   79.73%   +0.12%     
==========================================
  Files          29       30       +1     
  Lines        4261     4268       +7     
  Branches      542      543       +1     
==========================================
+ Hits         3392     3403      +11     
+ Misses        726      722       -4     
  Partials      143      143              

[webknjaz]

@itamarst thanks for looking into this! Too bad there's no backport for shutdown queues.

I have a few cosmetic requests but overall looks good. Could you tweak those? Thanks again!

[nijel]

The tests in translate-toolkit pass with this applied, so for us this fixes #769.

[itamarst]

OK, done.

[webknjaz]

Thanks!

[itamarst]

And I fixed the spelling issue too.

[webknjaz]

🎉 v11.1.2 just hit PyPI: https://pypi.org/project/cheroot/11.1.2/

• https://github.com/cherrypy/cheroot/releases/tag/v11.1.2
• v11.1.2 #796