UNITY Destroy()和DestroyImadiate()的区别

using System.Collections;
using System.Collections.Generic;
using System.Timers;
using UnityEngine;
using System.Diagnostics;
public class testdestroy : MonoBehaviour {

    GameObject cubeGo;
    Transform rootTrans;
    // Use this for initialization

    Stopwatch timer;
    void Start () {
        cubeGo = GameObject.Find("Cube");
        rootTrans = GameObject.Find("root").transform;

        timer = new Stopwatch();
    }
    
    // Update is called once per frame
    void Update () {
        if (Input.GetKey(KeyCode.LeftControl))
        {
            var go = Instantiate(cubeGo);
            go.transform.SetParent(rootTrans);
            
        }
        else if (Input.GetKey(KeyCode.A))
        {//11111111111
            for (int i = 0; i < rootTrans.GetChildCount(); ++i)
            {
                timer.Reset();
                timer.Start();
                Destroy(rootTrans.GetChild(i).gameObject);
                timer.Stop();

                UnityEngine.Debug.Log("1:time elipsed===:" + timer.Elapsed);
            }

            rootTrans.DetachChildren();
        }
        else if (Input.GetKey(KeyCode.D))
        {//2222222222
            while (true)
            {
                var cc = rootTrans.childCount;
                //UnityEngine.Debug.Log("cc============================" + cc);
                if (cc == 0)
                    break;
                timer.Reset();

                timer.Start();
                DestroyImmediate(rootTrans.GetChild(0).gameObject);
                timer.Stop();

                UnityEngine.Debug.Log("2:time elipsed===:" + timer.Elapsed);
            }

        }
        else if (Input.GetKey(KeyCode.F))
        {
            DestroyImmediate(cubeGo.transform);
        }
    }
}