… and bidirectional streams

…ccept the connect request, instead hold on to it

This changes the `quic::SendStream` trait to closer mimic the
`AsyncWrite` trait, but using a `impl Buf` rather than `&[u8]` which
removes the need to allocate and copy the byte slice to store it if
needed.

[s2n-quic::SendStream](https://github.com/aws/s2n-quic/blob/bf20c6dd148153802929a2514b444dcf5dd37fd1/quic/s2n-quic-h3/src/s2n_quic.rs#L364) uses this to enqueue the bytes for sending, which would require allocating if `&[u8]` was used.

Issue hyperium#78 discusses this API change which would remove the need for intermediate buffering.

See: hyperium#78 (comment)

This makes the SendStream significantly more flexible as it is no longer
constrained to sending only a single type of bytes.

Both `quinn` and `s2n` implemented SendStream for *any* type which
implemented `Buf`, rather than a specific type. See: https://github.com/aws/s2n-quic/blob/bf20c6dd148153802929a2514b444dcf5dd37fd1/quic/s2n-quic-h3/src/s2n_quic.rs#L358

Use of SendStream<B> was mixed throughout the code and supplying a type
for `B` was always necessary even at times where sending was not
necessary, which lead to the use of `PhantomData`, such as the
`RecvStream` impl for FrameStream. Often a `()` was used to indicate
this.

This leaked all the way up to the user facing api, where the user has to
decide upfront what type of buffer they will use for sending the request,
most often `Bytes` (see examples). This is unnecessary and needlessly
restrictive, and that `B` is in most cases a `PhantomData` where it is
used.

The new system moves the specific buffer to a generic to the send
function.

…nterval to quinn config so that webtransport connection does not close

This also removes the "phantom" generic on many types which is often
`Bytes` for an internal buffer type on the send streams

Introduced `BufRecvStream` which holds onto the already read data.

This prevents data loss when streams are transitioned from one type to
another, such as when reading the type and then constructing a decoded.
This was previously done manually through
`AcceptedRecvStream::into_stream` => `FrameStream::with_buf`, but was
error prone as the buffer could easily be forgotten when deconstructing
the frame stream later.

…eams but I sending server side uni_streams does not work

…add-webtransport

This reverts commit 0d49d38.

This reverts commit 9ec8012.

…heir way to access mods that used to be private like connection, streams, etc

…add-webtransport

…s` feature