EventDispatcher.cs

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace EventDispatcher
{
    public abstract class Event<T> where T : Event<T>
    {
        private bool hasFired;
        public delegate void EventListener(T info);
        private static event EventListener listeners;

        public static void RegisterListener(EventListener listener)
        {
            listeners += listener;
        }

        public static void UnregisterListener(EventListener listener)
        {
            listeners -= listener;
        }

        public void FireEvent()
        {
            if (hasFired)
            {
                throw new Exception("This event has already fired, to prevent infinite loops you can't refire an event");
            }
            hasFired = true;
            listeners?.Invoke(this as T);
        }
    }
}