ReadonlydirectoryReadonlydiscardedBytes at and after the damaged record that recovery could not retain.
Zero means a loss was detected whose extent the journal cannot measure -- a segment whose records are gone leaves nothing to count. Treat it as "unknown", not as "nothing lost", and read reason.
ReadonlyreasonReadonlysegment
Frames discarded while recovering a damaged journal. Emitted instead of failing recovery when the damage sits in the active segment, matching the Java client, which zeroes an active torn tail by policy and reports the residue through a WARN plus MmapSegment.tornTailBytes().