Sounds a reasonable contribution, thanks. But I think at lease one maintainer sponsor and two reviewers for this new core extension.

All extensions must be sponsored by an existing maintainer. Sponsorship means that the maintainer will shepherd the extension through design/code reviews. Maintainers can self-sponsor extensions if they are going to write them, shepherd them, and maintain them.

Each extension must have two reviewers proposed for reviewing PRs to the extension. Neither of the reviewers must be a senior maintainer. Existing maintainers (including the sponsor) and other contributors can count towards this number. The initial reviewers will be codified in the CODEOWNERS file for long term maintenance. These reviewers can be swapped out as needed.

See https://github.com/envoyproxy/envoy/blob/main/EXTENSION_POLICY.md for more detail.

If you are willing, I can help to review or even sponsor it (this extension should be simple and won't take too much bandwidth), but we still need another reviewer to ensure the quality of extension.

Or you can add this extension as contrib extension. contrib extension have a relatively loose requirement.

Seems OK to me to add if @wbpcode is willing to review.

LGTM. Thanks.

Hi, cc @mattklein123 could you also give a quick check in case I am missing something?

Few typos.
Should integration test be added to make sure that it works e-2-e?

LGTM. Thanks.

Nice!