Don't use private traits in public APIs #2051
Description
For example, hyper master currently has this:
impl<I, B, S, E> Future for Connection<I, S, E>
where
S: HttpService<Body, ResBody=B>,
S::Error: Into<Box<dyn StdError + Send + Sync>>,
I: AsyncRead + AsyncWrite + Unpin + 'static,
B: Payload + 'static,
B::Data: Unpin,
E: H2Exec<S::Future, B>,HttpService and H2Exec are both private traits, though. This makes it a huge pain for code working generically with connections to express the proper bounds in their code. You basically have to try to reverse engineer the impl bounds by bouncing off the compiler :(