This example for OOP2 class, showing how async functions are working on Dart

main.dart

void main(){
  
 performTasks();
  
}
  void performTasks () async{
    task1();
    String task2Result= await task2();
    task3(task2Result);
  }
void task1(){
  String result='task 1 data';
  print('Task 1 complete');
}
Future task2() async{
  Duration threeSeconds= Duration(seconds:3);
  String? result;
  
  await Future.delayed(threeSeconds,(){
    result='task 2 data';
    print('Task 2 complete');
  });
  
  return result!;
}

void task3(String task2Data){
  String result='task 3 data';
  print('Task 3 complete with $task2Data');
}