pruneTerminalTickets compared the cutoff against createdNanos, so the real
window to collect a reply was "TTL minus however long the task ran". A
delegation that ran longer than the 10-minute TTL was already past the cutoff
the moment it finished, so the next prune destroyed its reply.
That is the normal case here, not an edge case. Real delegated work runs well
past ten minutes. Three workers in one session did, and two of their complete
reports were lost. The reply lives only in Task.future, so pruning it discards
the worker's whole report, and fleet_poll{target} returns [] rather than
holding it — there is no fallback.
Task now stamps completedNanos from a whenComplete hook registered in its
constructor, so every completion path stamps it (a reply, the completion
fallback, a timeout, a failure, an abandon on teardown) without each one having
to remember to. The stamp is a boxed Long, not a long with a sentinel:
System.nanoTime may return any value, so no number can mean "not stamped yet".
A task that is done but not yet stamped is left for the next sweep.
createdNanos had no other reader and is removed.
The TTL still bounds tasks — an uncollected finished ticket is still evicted
once the TTL passes since it finished. Both halves are pinned by a test, and
the first one was proved by restoring the old comparison and watching it fail.
Tests run: 1032, Failures: 0, Errors: 0, Skipped: 0
Dai Ha