What step() reports.
step()
skipped is set only on the already-migrated no-op, and generation / elapsedMs only on a run that reached the replay loop, so all three are optional on the one shape.
skipped
generation
elapsedMs
Optional
What
step()reports.skippedis set only on the already-migrated no-op, andgeneration/elapsedMsonly on a run that reached the replay loop, so all three are optional on the one shape.