Unity中，不继承MonoBehaviour的类使用Mono的

实现一个单例MonoSys，外部调用它。
MonoSys自己维护一个MonoController。

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;

public class MonoController : MonoBehaviour
{
    public event Action ApplicationPauseEvent;
    public event Action ApplicationQuitEvent;
    public event Action UpdateEvent;
    public event Action<Scene, LoadSceneMode> SceneChangedEvent;

    private void OnEnable()
    {
        SceneManager.sceneLoaded += OnSceneLoaded;
    }
    private void OnDisable()
    {
        SceneManager.sceneLoaded -= OnSceneLoaded;
    }
    private void OnApplicationPause(bool pauseStatus)
    {
        if (pauseStatus)
        {
            ApplicationPauseEvent?.Invoke();
        }
    }
    private void OnApplicationQuit()
    {
        ApplicationQuitEvent?.Invoke();
    }

    private void Update()
    {
        UpdateEvent?.Invoke();
    }
    private void OnSceneLoaded(Scene scene, LoadSceneMode mode)
    {
        SceneChangedEvent?.Invoke(scene, mode);
    }
}
public class MonoSys
{
    private static MonoSys _instance;
    public static MonoSys Instance
    {
        get
        {
            if (_instance == null)
            {
                _instance = new MonoSys();
            }

            return _instance;
        }
    }
    private MonoController _monoController;
    private MonoSys()
    {
        var parentGo = GameObject.Find("Singleton");
        if (parentGo == null)
        {
            parentGo = new GameObject("Singleton");
            UnityEngine.Object.DontDestroyOnLoad(parentGo);
        }

        GameObject go = new GameObject(nameof(MonoController));
        go.transform.SetParent(parentGo.transform);
        _monoController = go.AddComponent<MonoController>();
    }

    public Coroutine StartCoroutine(IEnumerator routine)
    {
        return _monoController.StartCoroutine(routine);
    }

    public void StopCoroutine(IEnumerator routine)
    {
        if (_monoController != null)
        {
            _monoController.StopCoroutine(routine);
        }
    }

    public void AddApplicationQuitEvent(Action action)
    {
        _monoController.ApplicationQuitEvent += action;
    }

    public void RemoveApplicationQuitEvent(Action action)
    {
        _monoController.ApplicationQuitEvent -= action;
    }

    public void AddApplicationPauseEvent(Action action)
    {
        _monoController.ApplicationPauseEvent += action;
    }

    public void RemoveApplicationPauseEvent(Action action)
    {
        _monoController.ApplicationPauseEvent -= action;
    }

    public void AddUpdateEvent(Action action)
    {
        _monoController.UpdateEvent += action;
    }

    public void RemoveUpdateEvent(Action action)
    {
        _monoController.UpdateEvent -= action;
    }
    public void AddSceneChangedEvent(Action<Scene, LoadSceneMode> action)
    {
        _monoController.SceneChangedEvent += action;
    }
    public void RemoveSceneChangedEvent(Action<Scene, LoadSceneMode> action)
    {
        _monoController.SceneChangedEvent -= action;
    }

    public IEnumerator DelayCall(float delayTime, Action action, bool isRealTime = false)
    {
        var coroutine = DelayCallCoroutine();
        StartCoroutine(coroutine);
        return coroutine;
        
        IEnumerator DelayCallCoroutine()
        {
            if (isRealTime)
            {
                yield return new WaitForSecondsRealtime(delayTime);
            }
            else
            {
                yield return new WaitForSeconds(delayTime);
            }
            action?.Invoke();
        }
    }
}