`flush` looked dead — the only caller in the host is the `spike` dev subcommand — so
an audit sweep filed it as "wire it in or delete it". Both are wrong, and without
this note the next sweep will re-file it.
Wiring it in is refuted by control flow: both encode loops reach their exit only
AFTER the transport is gone (client disconnected, or the session stopped), so the AUs
a flush would recover have nowhere to go. And flush is the one call on this trait
that can BLOCK on a wedged encoder, on exactly the teardown path a stopped session
needs to finish promptly — the Linux direct-SDK NVENC retrieve-thread join is untimed,
so flushing there could hang a session that is already ending.
Deleting it is refuted by real consumers: `spike` encodes a FINITE clip and wants the
tail, and the `#[ignore]`d hardware smoke tests across the backends assert the drain
contract on real GPUs. Those are finite-stream users; a live session is not one.
Doc only, no behaviour change.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>