The only feature in this batch adding a real dependency, approved up front
and landed the same way tcptrace/ndt7 already do: an optional extra
(uv sync --extra quic), imported lazily inside measure_quic() so a missing
install degrades to a clear skip warning instead of a crash.
Verified the actually-installed aioquic 1.3.0 API directly rather than
assuming. connect() takes local_port but no local_host/source-address
parameter at all, so --quic structurally cannot honor --interface -
_quic_section() says so explicitly rather than silently measuring the
OS-default path under a report claiming a forced adapter. Its context
manager doesn't yield until the handshake finishes, so unlike the TLS RTT
probe's two-connection subtraction trick, handshake time here is timed
directly. HandshakeCompleted's fields matched what was expected; dropped
a planned quic_version field since aioquic has no clean public API for
it rather than reach into a private attribute.
quic_verdict(quic_ok, tcp_ok) is the actual payoff: QUIC failing while
plain TCP to the same host succeeds means the network specifically
drops or throttles UDP/443, silently degrading Chrome/YouTube's HTTP/3
preference in a way no TCP-based diagnostic would ever catch. Both
failing is ordinary unreachability already covered elsewhere, so it
stays silent rather than duplicating that finding.
Opt-in --quic, excluded from --full - an optionally-installed extra must
never become a silent requirement. Added the quic extra to the release
workflow's wheel-install verification.
Live-tested against real cloudflare.com/google.com: real handshakes,
ALPN h3 negotiated, correct end-to-end timing.
This completes the 16-feature extension batch from
plans/zesty-zooming-wilkinson.md (gitignored, local planning doc).
