Ember Upgrade onto fs2.io.tls

[ChristopherDavenport]

No description provided.

[rossabaker]

Hypothetical because it requires an unreleased version of fs2? I like the API cleanup a lot.

[ChristopherDavenport]

Yes, its currently on the snapshot that is unreleased, however its a major improvement IMO.

[rossabaker]

I jumped on this to see if it's ready while I'm preparing releases. All credit for the important work to Chris.

[rossabaker]

Still a compile error:

[error] /home/ross/src/http4s/ember-client/src/main/scala/org/http4s/ember/client/EmberClientBuilder.scala:86:95: type mismatch;
[error]  found   : F[Option[fs2.io.tls.TLSContext]]
[error]  required: F[Option[F[fs2.io.tls.TLSContext]]]
[error]           .fold(Sync[F].delay(TLSContext.system(blocker)).attempt.map(_.toOption))(_.some.pure[F])
[error]                                                                                               ^

[ChristopherDavenport]

This was changed afterwards due to comments from this PR, now I think the toOption stuff is now unecessary.

[rossabaker]

Is TLSContext.system(blocker) something we expect to fail, and want to swallow if it does? Maybe this type could be simplified to F[TLSContext]?

Compiling in my head with an unfamiliar API, so ignore me if this is nonsense.

[ChristopherDavenport]

This is analagous to what we do in blaze.

https://github.com/http4s/http4s/blob/master/blaze-client/src/main/scala/org/http4s/client/blaze/BlazeClientBuilder.scala#L304

[rossabaker]

Oh, right, to delay the construction for those pathological cases where the default throws. Ugh. Yeah, good call.