await for two Futures

main.dart

void main() async {
  int sum = await square(3) + await square(4);
  print('3^2 + 4^2 = $sum');
}

Future<int> square(int val) async {
  print('${DateTime.now()} started calculating $val^2');
  await Future.delayed(Duration(seconds: 1));
  int result = val * val;
  print('${DateTime.now()} finished calculating $val^2');
  return result;
}