如何在initState flutter中运行计时器？

import 'dart:async';

class MyWidget extends StatefulWidget {
  @override
  _MyWidgetState createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  Timer _timer;
  int _counter = 0;

  @override
  void initState() {
    super.initState();
    _timer = Timer.periodic(Duration(seconds: 1), (timer) {
      setState(() {
        _counter++;
      });
    });
  }

  @override
  void dispose() {
    _timer.cancel(); // 在组件销毁时取消计时器
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Text('Counter: $_counter');
  }
}