[#116] Fix retrieve buffer overflow

[elfenpiff]

Notes for Reviewer

The retrieve buffer can overflow when the publisher loans many samples and send them one by one without any more loans. The problem is, that the samples in the retrieve buffer are only recollected whenever a new loan is acquired. When we never have to call loan again since we have a big buffer of loaned samples on the publisher side, the retrieve buffer will overflow and the communication fails.

The solution is rather simple: Call retrieve_returned_samples before sending any new samples. In this way, we ensure that we reclaim all borrowed samples before we borrow (send) new samples to the receiver.

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
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

Use either 'Closes #123' or 'Relates to #123' to reference the corresponding issue.

Relates to #116

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (dfd44b1) 77.36% compared to head (dcdc80f) 77.36%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #117   +/-   ##
=======================================
  Coverage   77.36%   77.36%           
=======================================
  Files         181      181           
  Lines       19596    19598    +2     
=======================================
+ Hits        15160    15162    +2     
  Misses       4436     4436           

Files	Coverage Δ
iceoryx2/src/port/publisher.rs	83.33% <100.00%> (+0.10%)	⬆️