Allow to specify a status for streaming endpoints

[jvanbruegge]

Currently streaming endpoints are always returning 200 OK. With this it is not possible to implement e.g. Range Requests, as those need to return 206 Partial Content. This PR changes this.

[alpmestan]

Your other PR has been merged, so you can rebase this one now :)

[jvanbruegge]

Rebased

[alpmestan]

Modulo updating docs/tutorial/etc, this looks to me. @phadej @gbaz Any objection?

[phadej]

Test(s) would be great as well.

[jvanbruegge]

How would I write a test for this? I guess I somehow have to assert the status code, but I am not sure how to get that status with clientM. I am only using servant-server myself

[gbaz]

Hmm... the stream tests are in StreamSpec: https://github.com/gbaz/servant/blob/db13077ccb93223e606ace6f7a67ac9389375a6a/servant-client/test/Servant/StreamSpec.hs

You can probably test for status codes as in: https://github.com/gbaz/servant/blob/db13077ccb93223e606ace6f7a67ac9389375a6a/servant-client/test/Servant/ClientSpec.hs#L338

[jvanbruegge]

responseStatusCode, thats what I searched for. I only looked at the StreamSpec tests, my fault

[jvanbruegge]

Currently streaming endpoints only return a ResultStream, there is no way to get the status code. Should I add a Status entry on the ResultStream type, in addition to the IO Continuation?
I'm not sure how you would want to handle this. I haven't had (and will not for at least this week) have time to look deeper into the servant-client code base to take a look how normal responses handle this.

[jvanbruegge]

I can confirm that this works. I was able to implement HTTP range requests with Servant and Conduit: jvanbruegge/media-goggler@b77da5e