static void Main(string[] args)
        {
            CountdownBroadcaster broadcaster = new CountdownBroadcaster("Hello world", 5000);
            FirstSubscriber firstSubscriber = new FirstSubscriber(broadcaster);
            SecondSubscriber secondSubscriber = new SecondSubscriber();
            secondSubscriber.Register(broadcaster);

            broadcaster.Start();

            Console.ReadLine();

        }
 public void Unregister(CountdownBroadcaster broadcaster)
 {
     broadcaster.TimeElapsedEvent -= WriteToConsole;
 }
 public SecondSubscriber(CountdownBroadcaster broadcaster):this()
 {
     Register(broadcaster);
 }
 public FirstSubscriber(CountdownBroadcaster broadcaster)
     : this()
 {
     Register(broadcaster);
 }