[DART] Future 클래스 : delayed 팩토리 생성자 사용하기

import 'dart:async';

void main() async {
  await printWithDelay('테스트1');
  await printWithDelay('테스트2');
  await printWithDelay('테스트3');
}

const Duration duration = Duration(seconds: 1);

Future<void> printWithDelay(String message) async {
  await Future.delayed(duration);

  print(message);
}