public class AttackState
{
    public static class Events
    {
        public const string HitStart = "Hit Start";
        public const string HitEnd = "Hit End";
    }

    [SerializeField]
    [EventNames(typeof(Events))]// Use all string fields in the Events class.
    private ClipTransition _Animation;

    private void Awake()
    {
        _Animation.Events.SetCallback(Events.HitStart, OnHitStart);
        _Animation.Events.SetCallback(Events.HitEnd, OnHitEnd);
    }

    private void OnHitStart() { }
    private void OnHitEnd() { }
}