fix(metrics): prevent negative utilization on late messages

[esensar]

Summary

This prevents late messages from breaking expected utilization bounds, by clamping all late messages to the start of reporting period. Messages arrive in order, so that should not break the expected state (waiting or not waiting). Utilization metric can still be slightly inaccurate on late messages, but it was never meant to be completely accurate.

How did you test this PR?

Tested with the included unit tests.

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

References

• Fixes: Vector utilization metric emits negative values after upgrade to v0.49.0 #24060

Notes

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Sponsored by Quad9

[pront]

Looking good. Needs a rebase on latest master.

[bruceg]

Thank you @esensar! It's great to see this follow-up.