public void markAsUnread(Preferences prefs) {
setMarkedReadAt(Optional.empty());
prefs.clearMarkedReadAt(getRepoId(), getId());
}
public void markAsRead(Preferences prefs) {
LocalDateTime now = LocalDateTime.now();
setMarkedReadAt(Optional.of(now));
prefs.setMarkedReadAt(getRepoId(), getId(), getMarkedReadAt().get());
}