Stopping a DartPad app

main.dart

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

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

Timer? myTimer;

void runDart() {
  int iter = 0;
  myTimer = Timer.periodic(const Duration(milliseconds: 10), (timer) {
    iter++;
    int temp = iter %1000;
    print("iter = $iter");
    print("iter %1000 = $temp");
  });
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Center(
        child: ElevatedButton(
          child: const Text('Stop'),
          onPressed: () {
            myTimer?.cancel();
          },
        ),
      ),
    );
  }
}