Admission in Rust, C#, TypeScript and Python goes through one predicate,
window_admits: the 32-packet slot, a sequence at most 1,023 above the lowest
unacked one, and at most 4 MiB of payload above it. With nothing pending any
packet is admissible. Admission is FIFO: nothing overtakes a queued packet.
The single-packet send refuses on the same predicate instead of queueing a
packet and then reporting that it produced none. The receive window is stated
in docs/cultnet-transport-parity.md. Kotlin trails (Cut K3).
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>