AnimatorStateObserver

 public class AnimatorStateObserver
    {
        private Animator _animator;
        /// <summary>
        ///
        /// </summary>
        /// <typeparam name="int">Animation Hash</typeparam>
        /// <typeparam name="EmeraldAIState">State</typeparam>
        /// <returns></returns>
        private Dictionary<int, EmeraldAIState> _states;
        private Dictionary<int, Action> _onEnableActions;
        private Dictionary<int, Action> _onDisableActions;

        public AnimatorStateObserver (Animator animator, Dictionary<int, EmeraldAIState> states = null)
        {
            _animator = animator;
            _states = states ?? new Dictionary<int, EmeraldAIState> ();

            _onEnableActions = new Dictionary<int, Action> ();
            _onDisableActions = new Dictionary<int, Action> ();
        }

        public void Subscribe ()
        {
            foreach (var item in _states)
            {
                int key = item.Key;

                item.Value.OnEnable +=
                    (_onEnableActions[key] = () => Set (key, true));

                item.Value.OnDisable +=
                    (_onDisableActions[key] = () => Set (key, false));

            }
        }

        public void UnSubcribe ()
        {
            foreach (var item in _states)
            {
                int key = item.Key;

                item.Value.OnEnable -= _onEnableActions[key];
                _onEnableActions.Remove(key);

                item.Value.OnDisable -= _onDisableActions[key];
                _onDisableActions.Remove(key);
            }
        }

        private void Set (int hash, bool active)
        {
            _animator.SetBool (hash, active);
        }
    }