2f4f92a804
ci / rust (push) Has been cancelled
Final increment of the 1 Gbps data-plane rework — the recv counterpart of the sendmmsg work. The client recv path did one recvfrom + one Vec allocation per packet (and the pump's 300µs idle sleep could let packets pile up at line rate). - Transport gains recv_batch(&mut [Vec<u8>], &mut [usize]) -> count; default is a single scalar recv into out[0] (loopback + non-Linux). - UdpTransport overrides it on Linux with recvmmsg (MSG_DONTWAIT) draining up to N datagrams per syscall into the caller's reused buffers — no per-packet alloc. - Session::poll_frame owns a lazily-allocated recv ring (RECV_BATCH=32) and consumes it one packet at a time across calls, refilling with one recvmmsg when drained. Encapsulated: the punktfunk-client-rs + NativeClient pumps are unchanged, and draining a batch per syscall means the 300µs sleep no longer underdrains. Added UdpTransport::local_addr (used by the test, generally handy). ~125k → ~4k recv syscalls/sec at line rate, zero per-packet recv allocation. Verified: new recv_batch_drains_over_loopback test (50 datagrams drained intact via recvmmsg) + the existing loopback round-trip now runs through the batched poll_frame; full suite (35 + round-trip + 6) + clippy + fmt green. Decode-in-place (kill the per-packet open_from_wire alloc) is a separate later optimization. With A (sendmmsg) + B (paced send) + C (recvmmsg), the native data plane is batched + paced end to end. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>