fix: Eliminate 6s delay on concurrent H2 requests#3
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The previous passthrough rewrite moved quic_send into a spawned task for body forwarding. For GET requests (no body), the task completed immediately, dropping quic_send and closing the QUIC send half. The client interpreted this as stream termination and closed before the response arrived, causing 502 "Tunnel closed" on every request. Fix: Use an mpsc channel to forward H2 body chunks to the main task, which owns quic_send for the entire request lifetime. tokio::select! handles both body forwarding and response streaming concurrently.
The transparent streaming proxy kept TCP connections alive (HTTP/1.1 default), so local servers like Next.js never closed the connection after sending their response. This meant local_read.read() blocked indefinitely, delaying the tunnel stream close by ~6 seconds. Fix: Inject Connection: close header when rewriting Host headers for non-upgrade requests. WebSocket upgrade requests preserve the original Connection: Upgrade header.
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Summary
body_stream.data().awaitblocking on GET requeststokio::select!to keepquic_sendalive for the full request lifetimeConnection: closeon proxied HTTP/1.1 requests so local servers (Next.js, etc.) close the TCP connection after responding, instead of holding it open with keep-alive (~6s idle timeout). WebSocket upgrade requests are excludedBefore
All concurrent H2 requests stalled for ~6 seconds (serialized by body buffering + keep-alive)
After
Requests flow through instantly as a transparent bidirectional pipe
Test plan