如何防止FutureBuilder在数据不变的情况下进行重建？

FutureBuilder(
  key: ValueKey(data), // data是数据对象
  future: fetchData(),
  builder: (BuildContext context, AsyncSnapshot snapshot) {
    // 构建UI
  },
);

Builder(
  builder: (BuildContext context) {
    return FutureBuilder(
      future: fetchData(),
      builder: (BuildContext context, AsyncSnapshot snapshot) {
        // 构建UI
      },
    );
  },
);

class MyWidget extends StatefulWidget {
  final Data data;

  MyWidget({Key key, this.data}) : super(key: key);

  @override
  _MyWidgetState createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  Data _oldData;

  @override
  void didUpdateWidget(MyWidget oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (widget.data != _oldData) {
      // 数据发生变化，执行相应操作
    }
    _oldData = widget.data;
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
      future: fetchData(),
      builder: (BuildContext context, AsyncSnapshot snapshot) {
        // 构建UI
      },
    );
  }
}