- DatagramReader::feed is infallible (the oversize bound is enforced
at frame time; the same zombie category as 4014ba6's InvalidLength).
The Vec<Result> shape, the local adapter's dead InvalidData mapping,
and consumer.rs's `?` drop.
- The sender-block machinery test (root-gated veth fixture, auto-skip
without root): the peer address unassigned + the neighbor table
flushed pins the connected sender in a persistent WouldBlock/ENOBUFS
state; the test drives the WouldBlock stash, the readiness-Pending
arms, AND the accepted-byte high-water Pend in one behavior, then
resolves (addr assign + peer bind) and asserts the queued datagrams
drain and deliver. Jumbo MTU (65535) keeps IP fragmentation out of
the way; the block-state probe runs on a throwaway socket (an
oversized probe's partially-built skb chain stays corked on EAGAIN
and poisons the socket).
- pump_queue_to_socket's stash arm now matches ENOBUFS(105) alongside
WouldBlock — the blocked-neighbor state reports 105, and both mean
"the socket cannot take this datagram now".
- connect_udp's resolve-failure arm covered (an RFC 6761 .invalid
target maps to dial_failed; rootless).
- The no-witness tunnel_establisher wrapper covered (a harness
DialNoWitness mode + a full open round-trip through the wrapper).
Negative result pinned in the task doc: tokio 1.53 structurally masks
UDP ICMP errors out of the poll drive (poll_recv_ready/try_io mask
ERROR out of the read direction), so the recv-side ECONNREFUSED
mapping arm is unreachable through the pump's drive — it joins the
defensive list.
Coverage: 92.86% -> 93.91% lines (50 -> 41 uncovered, all deliberate).
Verification: cargo test + cargo test --all-features (91 tests),
clippy --all-targets --all-features, fmt, wasm32 check+clippy,
cargo doc — all clean.
glm-5.3-flash
63dbdb64a5