65d49f6430
The test burst 3×100 1200 B datagrams into an undrained loopback socket: at ~2.5 KB kernel truesize each, the default ~212 KB rmem holds only ~80, so on a starved CI runner (parallel release builds) the kernel silently dropped the overflow and the recv loop could never reach 300 — surfacing as WouldBlock after the 3 s timeout. Size the burst (3×20) to fit the default buffer even with zero concurrent draining, and give recv a starvation-tolerant 10 s. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>