dart-async

main.dart

import 'dart:async';

void main() {
  Future getName() async {
    // 打印时钟
    Timer.periodic(new Duration(seconds: 1), (timer) {
      final tick = timer.tick;
      print('时间过去$tick秒');
      if (tick >= 5) {
        timer.cancel();
      }
    });

    String name = await Future.delayed(Duration(seconds: 4), () => 'shuangyu');

    print(name);
  }

  getName();
}