IEnumerator （迭代器）

void Start()
    {
        StartCoroutine(LoadScene());
    }


IEnumerator LoadScene()
    {
        int i = 0;
        print("a:" + ++i);

        AsyncOperation ao = null;
        if (level1 == 1)
        {
            ao = SceneManager.LoadSceneAsync("Normal");
        }
        else if (level1 == 2)
        {
            ao = SceneManager.LoadSceneAsync("Woods");
        }
        else if (level1 == 3)
        {
            ao = SceneManager.LoadSceneAsync("Peak");
        }
        ao.allowSceneActivation = false;
        while (!ao.isDone)
        {
            print("b:" + ++i);

            if (ao.progress >= 0.9f)
            {
                GameObject.Destroy(Camera.main);
                ao.allowSceneActivation = true;
            }

            yield return null;

            if (ao.isDone)
            {
                Instantiate(mapManager).gameManager = this;
            }

            print("c:" + ++i);
        }

a:1
b:2
c:3
b:4
c:5