Example of Asynchronous Function

void main() {
  print("First Operation");   
  Future.delayed(Duration(seconds:3),()=>print('Second Big Operation'));
  print("Third Operation"); 
  print("Last Operation"); 
}

________________________________________________________________________________________________________

Example of Future class

// function that returns a future
Future<String> getUserName() async {
  return Future.delayed(Duration(seconds: 2), () => 'Mark');
}

// main function
void main() {
  print("Start");
  getUserName().then((value) => print(value));
  print("End");
}

________________________________________________________________________________________________________