[#507] waitset adjustments

[elfenpiff]

Notes for Reviewer

• DeadlineQueue::missed_deadlines() callback needs to return CallbackProgression so that the user is able to stop handling missed deadlines when required.
• WaitSet::try_wait_and_process was renamed to WaitSet::wait_and_process_once since the function was actually blocking in contrast what the name suggested with the try_ prefix
  • behavior adjusted, blocks until the first event arrives, then handles all events and returns, to make it usable in external event loops.
• WaitSet::wait_and_process and WaitSet::wait_and_process_once callbacks need to return CallbackProgression to terminate event handling whenever required - this replaces the buggy WaitSet::stop() call.

Pre-Review Checklist for the PR Author

1. Add sensible notes for the reviewer
2. PR title is short, expressive and meaningful
3. Relevant issues are linked in the References section
4. Every source code file has a copyright header with SPDX-License-Identifier: Apache-2.0 OR MIT
5. Branch follows the naming format (iox2-123-introduce-posix-ipc-example)
6. Commits messages are according to this guideline
   • Commit messages have the issue ID ([#123] Add posix ipc example)
   • Commit author matches Eclipse Contributor Agreement (and ECA is signed)
7. Tests follow the best practice for testing
8. Changelog updated in the unreleased section including API breaking changes
9. Assign PR to reviewer
10. All checks have passed (except task-list-completed)

Checklist for the PR Reviewer

• Commits are properly organized and messages are according to the guideline
• Unit tests have been written for new behavior
• Public API is documented
• PR title describes the changes

Post-review Checklist for the PR Author

1. All open points are addressed and tracked via issues

References

Closes #507

[codecov]

Codecov Report

Attention: Patch coverage is 80.00000% with 8 lines in your changes missing coverage. Please review.

Project coverage is 79.29%. Comparing base (5f6a0dc) to head (71c4db4).
Report is 47 commits behind head on main.

Files with missing lines	Patch %	Lines
iceoryx2/src/port/waitset.rs	78.94%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #509      +/-   ##
==========================================
+ Coverage   79.19%   79.29%   +0.10%     
==========================================
  Files         200      200              
  Lines       23716    23757      +41     
==========================================
+ Hits        18781    18838      +57     
+ Misses       4935     4919      -16     

Files with missing lines	Coverage Δ
iceoryx2-bb/posix/src/deadline_queue.rs	89.43% <100.00%> (-0.22%)	⬇️
iceoryx2/src/port/waitset.rs	79.32% <78.94%> (+1.75%)	⬆️

... and 16 files with indirect coverage changes

[orecham]

Curious - why is the C enum used? I guess it's because this is called directly by the C API?

[elfenpiff]

@orecham this is just the internal implementation. I need a C style callback in the C++ API that has the C++ iox::function stored in context and can be used as a callback in the C API.

[orecham]

Just one question.