Extracts the two-pump data-plane helper alknet ADR-078 deferred until
the shapes converged (they have: alktunnels POC pump_halves + alktty's
channels session). Purely additive.
- channels::pump::pump_bidi(channel, peer_read, peer_write) -> (u64, u64):
two joined pumps, shutdown-on-completion per direction; copy counts
for observability. The channel side is a single AsyncRead +
AsyncWrite value (the accept_bi BiStream); the peer side takes split
halves — the establisher's natural dial result (into_split).
- Return (u64, u64), not the review sketch's io::Result<(u64, u64)>:
both pumps swallow copy errors by contract (mid-stream error =
abrupt close, no error channel mid-stream per ADR-049 §6), so an
Err state would be dead code. Deviation recorded in ADR-050.
- alktty's three-pump session does not fit (exit future as a third
signal) and stays as-is, per the review's scope.
- Tests reproduce the POC's two-pump semantics through the helper:
bidirectional flow with exact counts, EOF-from-one-side completes
the other's shutdown (clean EOF at the far end), dead-source =
EOF-shaped teardown.
- ADR-050 records the decision, deviations, and two-way door type.
Verification: cargo test (625 passed, +2), clippy -D warnings, fmt
--check, doc clean, test --all-features clean, wasm32-unknown-unknown
check clean.
glm-5.3-flash
9c6fec17ca