h3 quinn example doesn't seem well behaved when tested with curl

[paulcdejean]

Here's the example, including example certs and example webroot: https://github.com/paulcdejean/quinn-h3-example

It's from the server.rs here: https://github.com/hyperium/h3/tree/master/examples

With very small tweaks to make error reporting better (basically just changing the function signature of main to async fn main() -> Result<(), anyhow::Error> )

I'm able to run the example successfully with:
RUST_BACKTRACE=1 cargo run -- --dir webroot

Then I submit a curl request and this happens:

~ $ /opt/homebrew/opt/curl/bin/curl --http3-only -k https://localhost:4433/index.html
Hello world!
curl: (18) HTTP/3 stream 0 reset by server

You can see the "Hello world!" contents of the index.html file in the webroot, is in fact returned. So this shows that things are mostly workingish.

In the logs for the server I get:

$ RUST_BACKTRACE=1 cargo run -- --dir webroot                            
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.04s
     Running `target/debug/h3-example --dir webroot`
2025-10-07T22:22:00.850834Z  INFO h3_example: serving webroot
2025-10-07T22:22:00.853676Z  INFO h3_example: listening on [::1]:4433
2025-10-07T22:22:04.314797Z  INFO h3_example: new connection established
2025-10-07T22:22:04.315908Z  INFO h3_example: successfully respond to connection
2025-10-07T22:22:04.316338Z ERROR h3_example: error on accept Remote error: Error undefined by h3: aborted by peer: the connection is being closed abruptly in the absence of any error

Curl version:

curl 8.16.0 (aarch64-apple-darwin24.4.0) libcurl/8.16.0 OpenSSL/3.6.0 zlib/1.2.12 brotli/1.1.0 zstd/1.5.7 AppleIDN libssh2/1.11.1 nghttp2/1.67.1 ngtcp2/1.16.0 nghttp3/1.12.0 librtmp/2.3
Release-Date: 2025-09-10
Protocols: dict file ftp ftps gopher gophers http https imap imaps ipfs ipns ldap ldaps mqtt pop3 pop3s rtmp rtsp scp sftp smb smbs smtp smtps telnet tftp ws wss
Features: alt-svc AsynchDNS brotli GSS-API HSTS HTTP2 HTTP3 HTTPS-proxy IDN IPv6 Kerberos Largefile libz NTLM SPNEGO SSL threadsafe TLS-SRP UnixSockets zstd

Operating system is MacOS 15.6.1 and cpu arch is apple silicon.