Implement into_inner to get the underlying stream

[hi-abhi]

Followup to the analogous change in tungstenite (snapview/tungstenite-rs#516) to get the underlying raw stream from a WebSocketStream.

There's an argument that into_inner on the WebSocketStream should return the WebSocket and then consumers call into_inner again, but that wraps AllowStd which is not public so I decide to return the underlying stream only which I think is fine.

This is a bit of an odd pull request in that it doesn't compile because a new version of tungstenite hasn't been cut yet. Once tungstenite = 0.28 is cut, hopefully this can be merged and be part of tokio-tungstenite = 0.28

[hi-abhi]

Checking back in on this, what type of release process/schedule do you have for tungstenite-rs and this crate? There's been a number of commits to tungstenite since 0.27 was cut, hoping this can make it in for 0.28 if it's not much trouble.

Thanks :)

[daniel-abramov]

what type of release process/schedule do you have for tungstenite-rs and this crate

We typically release a new version when there are substantial changes to the library, such as a noticeable performance improvement, a bug fix, a new feature, or a change in the behavior of an existing feature. There was no release since there have been no functional or performance changes (apart from some tiny ones) in tungstenite since 0.27.0.

hoping this can make it in for 0.28 if it's not much trouble

Alright, I've just published 0.28.0. Feel free to update the PR :)

NB: If that's the only change, I could then release 0.28.0 of tokio-tungstenite as well.

[hi-abhi]

Thanks, appreciate it. Just updated with the tungstenite version upgrade.

[daniel-abramov]

UPD: I've made a minor code change in master; please rebase to ensure the PR passes CI.