## Description

<!-- What does this PR change? Link related issues, e.g. `Fixes #123`. -->

## Motivation

<!--
Fill this section in; delete this comment when done.

Explain why this telemetry should be standardized. Focus on the decision or action it enables, not on how it is produced.

Include:

- **User journey:** what user journey does this support? For example: incident triage, cost allocation, quality evaluation, sampling decisions, capacity planning, security investigation.
- **Prior art:** where does this (or an equivalent) exist today outside of OpenTelemetry?
-->

## Prototype

<!--
Show end-to-end that the proposed convention can actually be produced from real libraries and consumed to answer the user journey.

Update the reference scenarios under `reference/scenarios/` to demonstrate this. If that isn't possible, explain why and provide an alternate prototype (e.g. instrumentation, demo, or dashboard).
-->

## Checklist

- [ ] Motivation section filled in above
- [ ] Reference scenarios updated for affected libraries
- [ ] Towncrier fragment added under `changelog.d/` for any change to the conventions that a consumer would care about. Editorial changes (typos, pure rewording, repo tooling) don't need an entry.

See [CONTRIBUTING.md]