feat(request-id): Add request-id constructor

[tottoto]

Motivation

Provides the same constructor of request-id as x-request-id.

Solution

Adds request-id constructor.

[jplatte]

This still has the x- 😄
But also, do you have a link to docs for the non-x--prefixed header?

[tottoto]

Fixed, and rebased to resolve the conflict.

[tottoto]

https://www.rfc-editor.org/rfc/rfc6648 deprecates "X-" prefix header, and request-id is also commonly used same as x-request-id.

[jplatte]

The RFC says "deprecates the convention for newly defined parameters" (emphasis mine) though. Do you have a source for the claim that it's commonly used?

[GlenDC]

FWIW might want to add a unit test to also test the request_id one. It's dumb logic, but it's easy enough to copy one of the x-request-id ones :)

[jlizen]

@tottoto I didn't see a lot of public usage. A smattering of larger clients (stripe, microsoft stuff, etc). But nothing reaching the point of convention.

Would be happy to accept a doc change to show the full custom header usage:

  const REQUEST_ID: HeaderName = HeaderName::from_static("request-id");

  let svc = ServiceBuilder::new()
      .set_request_id(REQUEST_ID, MyMakeRequestId::default())
      .propagate_request_id(REQUEST_ID)
      .service(handler);

It also might nice to offer a cleaner helper...

  let svc = ServiceBuilder::new()
      .emit_request_id("request-id", MyMakeRequestId::default())
      .service(handler);