optimeize unescape slash path

[chenylh]

Commit Message: Additional Description: Risk Level: Testing: Docs Changes: Release Notes: Platform Specific Features: [Optional Runtime guard:] [Optional Fixes #Issue] [Optional Fixes commit #PR or SHA] [Optional Deprecated:] [Optional API Considerations:]

[repokitteh-read-only[bot]]

Hi @chenylh, welcome and thank you for your contribution.

We will try to review your Pull Request as quickly as possible.

In the meantime, please take a look at the contribution guidelines if you have not done so already.

:cat:

Caused by: https://github.com/envoyproxy/envoy/pull/34934 was opened by chenylh.

see: more, trace.

[mattklein123]

Seems fine but is this actually faster?

/wait

[nezdolik]

@yanavlasov friendly ping