Update document

Docs/CodeTutorial3.md

@@ -121,3 +121,32 @@ IEnumerator Start()
 }
 ````
 
+**FairyGUI加载方案**
+
+注意：在FairyGUI的面板销毁的时候，将资源句柄列表释放，否则会造成资源泄漏。
+
+````c#
+// 资源句柄列表
+private List<AssetOperationHandle> _handles = new List<AssetOperationHandle>(100);
+
+// 加载方法
+private object LoadFunc(string name, string extension, System.Type type, out DestroyMethod method)
+{
+    method = DestroyMethod.None;
+    string location = $"FairyRes/{name}{extension}";
+    var handle = YooAssets.LoadAssetSync(location , type);
+    _handles.Add(handle);
+    return handle.AssetObject;
+}
+
+// 释放资源句柄列表
+private void ReleaseHandles()
+{
+    foreach(var handle in _handles)
+    {
+        handle.Release();
+    }
+    _handles.Clear();
+}
+````
+