First step of `quic/plans/2026-05-04-control-frame-retransmit.md`.
Pure type definitions, no behavior change yet — sets up the data
shape the next steps will populate from the writer (step 2) and
drain from ACK / loss-detection paths (steps 3–6).
RecoveryToken: sealed class mirroring neqo's
neqo-transport/src/recovery/token.rs:21 StreamRecoveryToken.
- Ack (singleton object): tracked but never retransmitted, so the
sent-packet map invariant ("every retained entry has at least
one token") holds for ACK-only packets too
- MaxStreamsUni / MaxStreamsBidi: receive-side stream-id cap
extension (RFC 9000 §19.11) — the frame whose loss tripped
the moq-rs cliff
- MaxData: connection-level data cap extension (§19.9)
- MaxStreamData: per-stream data cap extension (§19.10)
SentPacket: data class mirroring neqo's
neqo-transport/src/recovery/sent.rs::Packet. Held in a per-pn-space
map on QuicConnection (step 2 wires this up). Carries packet number,
send time, ack-eliciting flag, on-wire size, and the token list to
dispatch on loss.
Tests: 6 token tests (data-class equality, sealed-hierarchy
exhaustiveness, Ack singleton-ness) + 6 SentPacket tests (equality
across fields, copy semantics, ACK-only-with-Ack-token convention,
multi-token packet shape). All pass; full :quic test suite still
passes — types are purely additive.
Out of scope as documented in the plan: STREAM data retransmit,
CRYPTO retransmit, RESET_STREAM/STOP_SENDING/etc, congestion control,
0-RTT. Those are separate follow-ups.
https://claude.ai/code/session_01PYYez8a6sjiakyjAxsfCEQ
Claude
9e6fa3d3f0