push notify in game | unity3d | c#

using UnityEngine;
using System.Collections.Generic;

/*
 * Notification in your game
 * Call Notifications.AddMessage(YOUR_MESSAGE);
 * My settings in inspector https://imgur.com/a/6UmL884
 * for ask: discord: av.stn
 */

namespace avstn.notifications
{
    public class Notifications : MonoBehaviour
    {
        public float speedFadeOut;

        public int timeDisplayNotif = 3;

        public GUIStyle style;

        public Vector2 msgOffs;
        public Vector2 msgSize;

        private Vector2 _msgOffs;

        private float _alphaCh = 1;
        private bool isFadeOut = false;

        private List<string> messages;

        private static Notifications cache;

        private const int MAX_NOTIFY_MESSAGES = 5;

        private float AlphaCh
        {
            get { return _alphaCh; }
            set
            {
                _alphaCh = value;

                if (_alphaCh <= 0)
                {
                    isFadeOut = false;
                    messages.Clear();
                    _msgOffs = msgOffs;
                    _alphaCh = 1;
                }
            }
        }

        private void Awake()
        {
            cache = this;
        }

        private void Start()
        {
            messages = new List<string>();

            if (timeDisplayNotif <= 0)
                timeDisplayNotif = 3;
        }

        private void Update()
        {
            if (isFadeOut && AlphaCh > 0)
                AlphaCh -= Time.deltaTime * speedFadeOut;
        }

        private void OnGUI()
        {
            if (messages.Count == 0)
                return;

            Color col = GUI.color;

            GUI.color = new Color(col.r, col.g, col.b, _alphaCh);

            for (int i = 0; i < messages.Count; i++)
                GUI.Box(new Rect(new Vector2(_msgOffs.x, _msgOffs.y + (msgSize.y * i)), msgSize), messages[i], style);

            GUI.color = col;
        }

        public static void AddMessage(string message)
        {
            cache.addMessage(message);
        }

        private void addMessage(string msg)
        {
            CancelInvoke("runFadeOut");

            isFadeOut = false;
            _alphaCh = 1;

            if (messages.Count == MAX_NOTIFY_MESSAGES)
            {
                for (int i = 1; i < MAX_NOTIFY_MESSAGES; i++)
                    cache.messages[i - 1] = messages[i];

                messages[MAX_NOTIFY_MESSAGES - 1] = msg;
            }
            else
                messages.Add(msg);

            Invoke("runFadeOut", timeDisplayNotif);

            _msgOffs = new Vector2(msgOffs.x, msgOffs.y - (messages.Count * msgSize.y));
        }

        private void runFadeOut()
        {
            isFadeOut = true;
        }
    }
}