BetterEvent.cs

public class BetterEvent
{
    private List<System.Action> _list;

    public BetterEvent( int prealocate = 10 )
    {
        _list = new List<System.Action>( prealocate );
    }

    public void Add( System.Action callback )
    {
        _list.Add( callback );
    }

    public void Remove( System.Action callback )
    {
        _list.Remove( callback );
    }

    public void Invoke()
    {
        for ( int i = 0; i < _list.Count; i++ ) {
            _list[i].Invoke();
        }
    }

    public void Clear()
    {
        _list.Clear();
    }
}

public class BetterEvent<T>
{
    private List<System.Action<T>> _list;
    public BetterEvent( int prealocate = 10 )
    {
        _list = new List<System.Action<T>>( prealocate );
    }

    public void Add( System.Action<T> callback )
    {
        _list.Add( callback );
    }

    public void Remove( System.Action<T> callback )
    {
        _list.Remove( callback );
    }

    public void Invoke( T args )
    {
        for ( int i = 0; i < _list.Count; i++ ) {
            _list[i].Invoke( args );
        }
    }
}