updateMode method
Update access mode of the current user or of another topic subscriber
Implementation
Future<CtrlMessage> updateMode(String? userId, String update) {
var user = userId != null && userId != '' ? subscriber(userId) : null;
var am = user != null
? user.acs!.updateGiven(update).getGiven()
: getAccessMode().updateWant(update).getWant();
return setMeta(SetParams(sub: TopicSubscription(user: userId, mode: am)));
}