A packet that needed a slot and found none was neither held nor delivered: no
counter recorded it and the consumer reserved a hole nothing could ever backfill.
It now commits the gap to free a slot and takes the ordering decision once more
against the sequence that commit left behind, bounded to one retry; past that it
is delivered in order with the counters it skipped as its `lost`, never flagged
late, because a packet ahead of the sequence has no hole to be looked up by. A
duplicate can now replace its slot at a full ring, as hold_packet's own comment
already promised, and the 20 ms default window is a named constant.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Fix the false trailing clause in the udps_stats_t::late_resequenced comment,
move udps_held_t from the tunable-limits section to internal-state next to
udps_slot_t, and add braces to three braceless if bodies to match house style.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
