Another pub-sub system for loose coupling.

Event.cs

/*
// Example Usage:

public class SomeEv : Event<SomeEv> { }

public class SomeOtherEv : Event<SomeOtherEv> { }

public class EVTest : MonoBehaviour
{
    void Start()
    {
        //use pooling
        SomeOtherEv.Subscribe(OnEv);
        var e = SomeEv.New();
        e.Publish();
        SomeEv.Dispose(e);
        //or not...
        SomeOtherEv.New().Publish().Dispose();
    }

    void OnEv(SomeOtherEv obj)
    {
        Debug.Log(obj);
    }
}
*/

public class Event<T> : System.IDisposable where T : Event<T>, new()
{
    static Stack<T> pool = new Stack<T>();
    static List<System.Action<T>> subscribers = new List<System.Action<T>>();

    public static T New()
    {
        T ev;
        if (pool.Count > 0)
            ev = pool.Pop();
        else
            ev = new T();
        return ev;
    }

    public static void Dispose(T ev) => pool.Push(ev);

    public T Publish()
    {
        var ev = (T)this;
        for (int i = 0, count = subscribers.Count; i < count; i++)
            subscribers[i](ev);
        return ev;
    }

    public static void Subscribe(System.Action<T> evListener) => subscribers.Add(evListener);

    public static void Unsubscribe(System.Action<T> evListener)
    {
        var idx = subscribers.IndexOf(evListener);
        subscribers[idx] = subscribers[subscribers.Count - 1];
        subscribers.RemoveAt(subscribers.Count - 1);
    }

    public static void Clear() => subscribers.Clear();

    public void Dispose() => Dispose((T)this);
}