如何在flutter中暂停和恢复quiver.async CountdownTimer

import 'package:flutter_countdown_timer/flutter_countdown_timer.dart';

CountdownTimer _countdownTimer;

// 初始化计时器
void initializeCountdownTimer() {
  _countdownTimer = CountdownTimer(
    Duration(seconds: 10), // 设置倒计时的时长
    Duration(seconds: 1), // 设置计时器的间隔
  );
}

void pauseCountdownTimer() {
  _countdownTimer.pause();
}

void resumeCountdownTimer() {
  _countdownTimer.resume();
}

import 'package:flutter/material.dart';
import 'package:flutter_countdown_timer/flutter_countdown_timer.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Countdown Timer Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  CountdownTimer _countdownTimer;

  @override
  void initState() {
    super.initState();
    initializeCountdownTimer();
  }

  // 初始化计时器
  void initializeCountdownTimer() {
    _countdownTimer = CountdownTimer(
      Duration(seconds: 10), // 设置倒计时的时长
      Duration(seconds: 1), // 设置计时器的间隔
    );
  }

  // 暂停计时器
  void pauseCountdownTimer() {
    _countdownTimer.pause();
  }

  // 恢复计时器
  void resumeCountdownTimer() {
    _countdownTimer.resume();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Countdown Timer Demo'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            CountdownTimer(
              endTime: DateTime.now().millisecondsSinceEpoch + 10000, // 设置倒计时的结束时间
              textStyle: TextStyle(fontSize: 32, fontWeight: FontWeight.bold),
              onEnd: () {
                print('Countdown Timer Ended');
              },
            ),
            SizedBox(height: 20),
            RaisedButton(
              onPressed: pauseCountdownTimer, // 暂停计时器
              child: Text('Pause'),
            ),
            RaisedButton(
              onPressed: resumeCountdownTimer, // 恢复计时器
              child: Text('Resume'),
            ),
          ],
        ),
      ),
    );
  }
}