当我再次切换到选项卡时，如何停止我未来的构建器重新加载？- Flutter/dart

import 'package:flutter/material.dart';

class MyPage extends StatefulWidget {
  @override
  _MyPageState createState() => _MyPageState();
}

class _MyPageState extends State<MyPage> with AutomaticKeepAliveClientMixin {
  @override
  bool get wantKeepAlive => true;

  @override
  Widget build(BuildContext context) {
    super.build(context); // 必须调用super.build(context)
    
    return Scaffold(
      appBar: AppBar(
        title: Text('My Page'),
      ),
      body: Container(
        child: Text('Content'),
      ),
    );
  }
}