How soon a final terminal that found shards missing looks again. The browser sends the terminal first
and re-sends its unacknowledged shards right after it (all keepalive), so they normally land within a
second or two; when the tab closed right after End, no close follows to trigger assembly. A re-check
that is still incomplete comes back Deferred, and the scheduler then arms the forced-Partial grace.
How soon a final terminal that found shards missing looks again. The browser sends the terminal first and re-sends its unacknowledged shards right after it (all
keepalive), so they normally land within a second or two; when the tab closed right after End, no close follows to trigger assembly. A re-check that is still incomplete comes backDeferred, and the scheduler then arms the forced-Partialgrace.