作用：批量修改Prefab中的内容，比如Prefab中添加了许多EditorOnly的物件，现在用工具批量删除

方法一：断开所有连接，重新组装Prefab，不推荐
var prefabObj = AssetDatabase.LoadAssetAtPath<GameObject>(prefabFilename);
var newInstance = GameObject.Instantiate(prefabObj);
    // Edit: UnityEngine.Object.DestroyImmediate();
    // Edit: GameObject.DestroyImmediate(obj);
PrefabUtility.SaveAsPrefabAssetAndConnect(newInstance, newPath, InteractionMode.AutomatedAction);
GameObject.DestroyImmediate(newInstance);

方法二：保持Prefab内的嵌套
var prefabObj = PrefabUtility.LoadPrefabContents(prefabFilename);
    // Edit: UnityEngine.Object.DestroyImmediate();
    // Edit: GameObject.DestroyImmediate(obj);
PrefabUtility.SaveAsPrefabAsset(prefabObj, newPath);
PrefabUtility.UnloadPrefabContents(prefabObj); // 注意调用此API，否则UnityCrash！