What are Dart async streams and how do I use them?

What are Dart async streams and how do I use them?

Dart async streams are a way to handle asynchronous data. They allow you to listen to a sequence of events over time.

Can you give me an example of how to create a stream in Dart?

Sure! You can create a stream using the Stream class. For example:

Stream<int> countStream() async* {
  for (int i = 1; i <= 5; i++) {
    await Future.delayed(Duration(seconds: 1));
    yield i;
  }
}

How do I listen to the events from this stream?

You can listen to the stream using the listen method. Here's how:

countStream().listen((data) {
  print('Received: $data');
});

What happens if I want to cancel the subscription?

You can cancel the subscription by storing the subscription returned by listen and calling cancel() on it. For example:

var subscription = countStream().listen((data) {
  print('Received: $data');
});

// To cancel:
subscription.cancel();