public void RemoveWiper(AWiper wiper)
 {
     lock (wipers) {
         wipers.Remove(wiper);
     }
     wiper.Stop();
     wiper.SetResources(null);
     wiper.SetManager(null);
 }
 public void AddWiper(AWiper wiper)
 {
     wiper.SetResources(resourceHandles);
     wiper.SetManager(this);
     wiper.Start();
     lock (wipers) {
         wipers.Add(wiper);
     }
 }