Stream example

main.dart

// asynchronous data
main() async {
//   Duration interval = Duration(seconds: 1);
//   Stream<int> stream = Stream<int>.periodic(interval, callback);

//   List l=[1,2,1,2,3,4,5,6];
//     Stream stream = Stream.fromIterable(l);

  Map<dynamic, int> map = {1: 1, 'a': 10, 'b': 20, 3: 2, 4: 4, 6: 5};
  Stream stream = Stream.fromIterable(map.entries);

  await stream
      .where((i) => i.key.runtimeType == int)
//       .takeWhile((i) => i.runtimeType == String)
      .listen((i) => print(i.value))
      .onDone(() => print("done"));

  print("Running");
//   await for(int i in stream){
//     print(i);
//   }
}

// This callback modify the given value to even number.
int callback(int value) {
  return (value + 1) * 2;
}