No graceful connection draining on shutdown in Rust (and TS): in-flight requests dropped on SIGTERM

[abienkowski]

Summary

On SIGTERM/SIGINT, the Go implementation drains in-flight requests via http.Server.Shutdown with a 30s timeout (go/main.go:92-97). The Rust implementation breaks its accept loops and exits main, which drops the tokio runtime — and with it any in-flight serve_connection tasks, aborting responses mid-flight.

Found during the code review of #27 (which rewrote the Rust shutdown path but preserved this pre-existing behavior — it is not a regression from that PR; the old single-listener code behaved the same way).

Affected implementation(s)

• Rust
• Go (reference behavior — already drains)
• TypeScript (worth auditing while at it: confirm server.close() semantics wait for in-flight requests)

Expected behavior

On shutdown signal:

1. Stop accepting new connections (already done).
2. Allow in-flight requests to complete, up to a 30s deadline (matching Go).
3. Exit after drain or deadline, whichever comes first.

Suggested fix (Rust)

Track connections in a tokio::task::JoinSet (or a counter + notify), and on shutdown call hyper's Connection::graceful_shutdown on active connections, then await the set with tokio::time::timeout(Duration::from_secs(30), ...).

Context

Split out from the review follow-ups on PR #27. Related: #25.