allow tracking ResponseHeaders

[ryskajakub]

What is the problem this feature would solve?

when I want to declare some response headers from endopint, I have no option, how to declare them in API.

What is the feature you are proposing to solve the problem?

allow declaring something like this in API:
.addSuccess({ responseBody: ... , responseHeaders }),

when this declaration is in use, I would return something like this in the handler:

 return Effect.suceed({ responseBody: { a: "b" }, responseHeaders: { "ETag": "deadbeef" } })

What alternatives have you considered?

I have workaround,

1. use Transform annotation to properly specify response headers in the swagger
2. use .handleRaw to handle the endpoint, which is not very typesafe and I can basically return any response and the code will still typecheck.

[ryanbas21]

Just commenting that i'm refactoring an older effect-http api, and this seems to be missing (either from the docs or ability to do it other than the work around above).

a .setResponseHeaders method would be awesome.