[#698] Fix 'UnixDatagramSender' blocking send calls

[elBoberido]

Notes for Reviewer

It seems there was a copy&paste error in the UnixDatagramSender::blocking_send and UnixDatagramSender::timed_send methods. Instead of setting the the socket to blocking, it was set to non-blocking. This PR fixes the bug.

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  • Commit messages have the issue ID ([#123] Add posix ipc example)
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Checklist for the PR Reviewer

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Post-review Checklist for the PR Author

• All open points are addressed and tracked via issues

References

Closes #698