allowedLaggingTasks int64,
allowedLagging time.Duration,
// AsTime is nil-safe: a nil timestamp reports as epoch.
ackVisUnset := remoteProgress.AckedTaskVisibilityTime.AsTime().Equal(time.Unix(0, 0))
if localShard.MaxReplicationTaskId > 0 && remoteProgress.AckedTaskId == 0 && ackVisUnset {
// Not ready, but leave laggingTasks/timeLag at zero so this shard can't win the
// Max* comparisons in the caller (i.e. can't surface the bogus now-since-1970 lag).