游易光年的Unity3D测试题，不明白哪里错了

题目：游戏中会出现很多计时器，比如建筑建造时间，商店刷新计时，限时活动等，用文字和伪代码结合的形式写出怎么管理这些计时器，答案尽量解耦和易读，并需要考虑以下两点：

a.计时器倒计时的UI显示

b.到时间后需要执行的逻辑

我的代码：

遵循三层架构，倒计时是临时使用也不需要事件，难道是商业项目中的实现完全不同？

public class TestUIPanel : SingletonMonoGlobal<TestUIPanel>
    {
        //时间显示的组件
        public Text timeText;

        public void SetTime(int second)
        {
            timeText.text = second.ToString();
        }
    }
    // 控制层
    public class BuildMgr
    {
        //注册事件
        void StartBuild(int buildTime)
        {
            //开启定时器
            TimeMgr.Instance.StartCountDown(buildTime,
            seconds => TestUIPanel.Instance.SetTime(seconds),
            FinishBuild);
        }
        //完成建造
        void FinishBuild() { }
    }
    // 具体数据处理 --数据层
    public class TimeMgr : SingletonMonoGlobal<TimeMgr>
    {
        public event Action<int> onTimeChange;

        public void StartCountDown(int seconds, Action<int> onTimeChange, Action onCountDownFinish)
        {
            StartCoroutine(StartCountDownAsync(seconds, onTimeChange, onCountDownFinish));
        }

        IEnumerator StartCountDownAsync(int seconds, Action<int> onTimeChange, Action onCountDownFinish)
        {
            while (seconds > 0)
            {
                yield return new WaitForSeconds(1f);
                seconds--;
                onTimeChange?.Invoke(seconds);
            }
            onCountDownFinish?.Invoke();
        }
    }

用ai生成了一下破案了，要将timer对象化并且使用对象池，没做过这种业务确实很难想到

// Timer.cs
public class Timer
{
    public float Duration { get; private set; }
    private float elapsedTime;
    private bool isRunning;
    public event Action OnTimerCompleted;

    public Timer(float duration, Action onTimerCompleted = null)
    {
        Duration = duration;
        OnTimerCompleted = onTimerCompleted;
    }

    public void Start() { isRunning = true; elapsedTime = 0f; }
    public void Stop() { isRunning = false; }
    public void Update(float deltaTime)
    {
        if (!isRunning) return;

        elapsedTime += deltaTime;
        if (elapsedTime >= Duration)
        {
            isRunning = false;
            OnTimerCompleted?.Invoke();
        }
    }

    public float GetTimeRemaining() => Duration - elapsedTime;
}

// TimerManager.cs
public class TimerManager : MonoBehaviour
{
    private List<Timer> timers = new List<Timer>();

    public Timer CreateTimer(float duration, Action onTimerCompleted)
    {
        var timer = new Timer(duration, onTimerCompleted);
        timers.Add(timer);
        timer.Start();
        return timer;
    }

    private void Update()
    {
        float deltaTime = Time.deltaTime;
        for (int i = timers.Count - 1; i >= 0; i--)
        {
            timers[i].Update(deltaTime);
            if (!timers[i].IsRunning) timers.RemoveAt(i);
        }
    }
}

// UI更新示例
public class TimerUI : MonoBehaviour
{
    [SerializeField] private Text timerText;
    private Timer timer;

    private void Start()
    {
        timer = TimerManager.Instance.CreateTimer(60f, OnTimerComplete);
        InvokeRepeating(nameof(UpdateUI), 0f, 1f);
    }

    private void UpdateUI()
    {
        if (timer != null)
            timerText.text = timer.GetTimeRemaining().ToString("F1");
    }

    private void OnTimerComplete()
    {
        timerText.text = "Complete!";
    }
}