Handle on waiting (backport #1562)

[mergify]

Conflict resolved from #1483

---

This is an automatic backport of pull request #1562 done by Mergify.

[mergify]

Cherry-pick of af4b48f has failed:

On branch mergify/bp/iron/pr-1562
Your branch is up to date with 'origin/iron'.

You are currently cherry-picking commit af4b48f.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   controller_manager/controller_manager/controller_manager_services.py
	modified:   controller_manager/controller_manager/hardware_spawner.py
	modified:   controller_manager/controller_manager/unspawner.py
	modified:   controller_manager/doc/userdoc.rst

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   controller_manager/controller_manager/spawner.py
	both modified:   controller_manager/test/test_spawner_unspawner.cpp

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[codecov]

Codecov Report

Attention: Patch coverage is 58.24176% with 76 lines in your changes missing coverage. Please review.

Project coverage is 62.08%. Comparing base (ae2ed7c) to head (9148241).
Report is 18 commits behind head on iron.

Files	Patch %	Lines
controller_manager/test/test_spawner_unspawner.cpp	56.32%	12 Missing and 64 partials ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             iron    #1681       +/-   ##
===========================================
- Coverage   87.45%   62.08%   -25.38%     
===========================================
  Files         101      102        +1     
  Lines        8078    11775     +3697     
  Branches      711     8447     +7736     
===========================================
+ Hits         7065     7310      +245     
- Misses        717      747       +30     
- Partials      296     3718     +3422     

Flag	Coverage Δ
unittests	62.08% <58.24%> (-25.38%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...er_manager/test/controller_manager_test_common.hpp	90.00% <100.00%> (+0.93%)	⬆️
controller_manager/test/test_spawner_unspawner.cpp	56.37% <56.32%> (-42.24%)	⬇️

... and 63 files with indirect coverage changes