Simple practice code for using Dart Future object.

future_example.dart

import 'dart:async';

void main() {
  Future<int>.delayed(Duration(seconds: 3), () {
    return 100;
  }).then((value) {
    print(value);
  }).then((value) {
    throw Exception();
  }).catchError((exception) {
    print("exception happened");
  }).whenComplete(() {
    print("everything is now complete!");
  }).then((value) {
    print("I get printed after everything was completed :)");
  });
  
  print("waiting..");
}

In order to test this sample code, just go to https://dartpad.dev/ and copy-paste all the code from this Gist