unity中加载下一个场景且不销毁当前场景的方法

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

public class TEST : MonoBehaviour {

    public Button btn;

    public void Start()
    {
        btn.onClick.AddListener(() => Load());
    }

    public void Load()
    {
        AsyncOperation  ass=SceneManager.LoadSceneAsync("02",LoadSceneMode.Additive);
    }


}

    // 摘要: 
    //     Used when loading a scene in a player.
    public enum LoadSceneMode
    {
        // 摘要: 
        //     Closes all current loaded scenes and loads a scene.
        Single = 0,
        //
        // 摘要: 
        //     Adds the scene to the current loaded scenes.
        Additive = 1,
    }