using System;

public static class Program

{

    static Action<string> exampleEvent;

    public static void Main()

    {

        var token = exampleEvent.Listen(Console.WriteLine);

        exampleEvent?.Invoke("Girls!");

        token.Dispose();

        exampleEvent?.Invoke("No more Girls :(");

    }

    public static ListenerToken Listen<T>(this Action<T> eventDelegate, Action<T> listenerDelegate){

        eventDelegate += listenerDelegate;

        return new ListenerToken(eventDelegate, listenerDelegate);

    }

    public struct ListenerToken : IDisposable{

        public Delegate Event;

        public Delegate Listener;

        public ListenerToken(Delegate eventDelegate, Delegate listenerDelegate){

            Event = eventDelegate;

            Listener = listenerDelegate;

        }

        public void Dispose(){

            Delegate.Remove(Event, Listener);

        }

    }

}