/// <summary>
 /// Registers new subscriber to the list of subscribers - when notify is called
 /// then all currently registered subscribers are called.
 /// </summary>
 /// <param name="subscriber">New subscriber that is registered.</param>
 public void Attach(SettingsSubscriber subscriber)
 {
     if (!Subscribers.Contains(subscriber))
     {
         Subscribers.Add(subscriber);
     }
 }
 /// <summary>
 /// Removes the subscriber from the list of subscribers - when notify is called
 /// then all currently registered subscribers are called.
 /// </summary>
 /// <param name="subscriber">Subscriber should be unregister, i.e. removed from the list of subscribers.</param>
 public void Detach(SettingsSubscriber subscriber)
 {
     if (Subscribers.Contains(subscriber))
     {
         Subscribers.Remove(subscriber);
     }
 }
 public void AddSubscriber(SettingsSubscriber subscriber)
 {
     _subscribers.Add(subscriber);
 }