does quiche/tokio-quiche support RFC 9297?

I notice quic-go http3 package support RFC 9297, but tokio-quiche doesn't mention it, in fact I only found

```rust
/// Set the `SETTINGS_ENABLE_CONNECT_PROTOCOL` HTTP/3 setting.
/// See
pub enable_extended_connect: bool,
```

in `Http3Settings`, it is not http datagram(RFC 9297)

Start by reading tokio-quiche's Http3Settings and its enable_extended_connect setting, then compare the implementation with RFC 9297. Determine whether HTTP datagram support is already present or what project entry points and tests would need coverage; done means the RFC 9297 support status is established and any required behavior is verified.

Written by the indexing model from the issue text.