as_hal api examples

[cwfitzgerald]

Connections
Link to the issues addressed by this PR, or dependent PRs in other repositories

When one pull request builds on another, please put "Depends on
#NNNN" towards the top of its description. This helps maintainers
notice that they shouldn't merge it until its ancestor has been
approved. Don't use draft PR status to indicate this.

Description
Describe what problem this is solving, and how it's solved.

Testing
Explain how this change is tested.

Squash or Rebase?

If your pull request contains multiple commits, please indicate whether
they need to be squashed into a single commit before they're merged,
or if they're ready to rebase onto trunk as they stand. In the
latter case, please ensure that each commit passes all CI tests, so
that we can continue to bisect along trunk to isolate bugs.

Checklist

• Run cargo fmt.
• Run taplo format.
• Run cargo clippy --tests. If applicable, add:
  • --target wasm32-unknown-unknown
• Run cargo xtask test to run tests.
• If this contains user-facing changes, add a CHANGELOG.md entry.