refactor(io,tls,ws)!: use pin-project-lite

[Berrysoft]

I will try TAIT after this PR.

[Copilot]

Pull request overview

This PR updates the compio-io compat adapter and downstream TLS/WebSocket integration to use pin-project-lite-based pinning, adjusting rustls stream types to be pinned and tightening various generic bounds accordingly.

Changes:

• Refactor compio_io::compat::AsyncStream to use pin_project_lite + PhantomPinned and update call sites to pin the stream before using futures_util extension traits.
• Update rustls integration to wrap compat streams as Pin<Box<AsyncStream<_>>> (and adjust related From impls / acceptor types).
• Add Unpin bounds to several public APIs (TlsConnector, TlsAcceptor, websocket TLS helpers) to satisfy the new compat adapter constraints.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
compio-ws/src/tls.rs	Tightens stream bounds to Unpin for TLS/plain wrapping to match updated TLS connector constraints.
compio-tls/src/stream.rs	Changes rustls inner stream type to Pin<Box<AsyncStream<_>>> and tightens TlsStream trait impl bounds.
compio-tls/src/rtls.rs	Updates rustls lazy acceptor/handshake wrapper types to use pinned compat streams and adds Unpin bounds.
compio-tls/src/adapter.rs	Pins compat streams for rustls connect/accept and adds Unpin to public generic bounds.
compio-io/src/compat/async_stream.rs	Switches to pin-project-lite, makes AsyncStream !Unpin, and reworks internal pin/borrow handling.
compio-io/tests/compat.rs	Updates tests to pin AsyncStream before using futures_util extension traits.
compio-io/Cargo.toml	Adds optional pin-project-lite dependency and wires it into the compat feature.

Comments suppressed due to low confidence (2)

compio-tls/src/adapter.rs:89

• TlsConnector::connect now requires S: Unpin even though only the rustls branch needs pinning (native-tls / py-dynamic-openssl paths don’t inherently require Unpin). This is a public API tightening that can break downstream users with !Unpin streams.

If possible, keep the original bound and add Unpin only when the rustls feature is enabled/used (e.g., via a rustls-specific helper method, a cfg-gated impl, or by adjusting compat::AsyncStream so it doesn’t require S: Unpin).

    pub async fn connect<S: AsyncRead + AsyncWrite + Unpin + 'static>(
        &self,
        domain: &str,
        stream: S,
    ) -> io::Result<TlsStream<S>> {

compio-tls/src/stream.rs:133

• TlsStream<S>’s AsyncRead/AsyncWrite impls now require S: Unpin, which is a public behavior change (some downstream S types that were previously supported may no longer compile). If this is only needed for the rustls backend, consider constraining Unpin to the rustls-specific path/types rather than the blanket impl bounds, or document this as a breaking change.

impl<S: AsyncRead + AsyncWrite + Unpin + 'static> AsyncRead for TlsStream<S> {
    async fn read<B: IoBufMut>(&mut self, mut buf: B) -> BufResult<usize, B> {
        let slice = buf.as_uninit();
        slice.fill(MaybeUninit::new(0));
        // SAFETY: The memory has been initialized

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[George-Miao]

LGTM