Observability

Pass --qlog <dir> to either side to emit xquic qlog. Per-path byte counts confirm that within-stream multipath is actually splitting a flow across paths — the key signal that aggregation is working. (xquic must be built with XQC_ENABLE_EVENT_LOG=ON, which scripts/build-xquic.sh does.)

Metrics

• --metrics-interval <sec> periodically logs per-path stats as mq.conn / mq.path logfmt lines. On the server it logs the most-recently-accepted TCP and gateway connection; on the client it logs the proxy connection (and the gateway connection when --gateway is set).
• --request-metrics (server, gateway) emits one mq.req logfmt line per gateway request (method/status/target/ttfb/origin_protocol/cache/…). Opt-in and independent of --metrics-interval.

Testing

After building, run the bundled test suite:

ctest --test-dir build --output-on-failure

It covers wire framing, the relay/flow state machine, ingress parsing, the gateway request path, and the TLS MITM crypto core, alongside end-to-end scripts for multipath aggregation, the full gateway chain, UDP relay, and transparent capture. Tests that need root or NET_ADMIN (the multipath and transparent-capture end-to-end runs) skip automatically when run unprivileged.