markSeenOmni method
Implementation
bool markSeenOmni(String shortLink) {
//set this entry as seen
ModeratorEntry? m = data.read(shortLink);
if (m == null) return false;
if (_omni.isSeen(m.hint)) return true;
//refresh for cache
_dirty = true;
return _omni.markSeen(m.hint);
}