Update long running isolate sample to use run() #165
Description
I have this example from @lrhn that could be used to update long_running_isolate.dart
In Lasse's words: This is a fairly primitive version of remote-running a stream function, it doesn't forward pause/resume/cancel calls on the subscription, and it stops on the first error. It does show how to send multiple events back from the other isolate.
import "dart:isolate"; Stream<T> runStream<T>(Stream<T> Function() remoteStream) => Stream.multi((controller) async { // New port for event messages. var port = RawReceivePort(); port.handler = (message) { var list = message as List; if (list.length == 1) { controller.add(list[0] as T); } else { controller.addError(list[1] as Object, list[2] as StackTrace); } }; // Run in other isolate, receive stream events on `port`. try { await Isolate.run(_remoteStream(remoteStream, port.sendPort)); // Returns when stream done. } catch (e, s) { controller.addError(e, s); } finally { port.close(); controller.close(); } }); // Creates an argument to `Isolate.run` from a `Stream Function()` and a port. Future<void> Function() _remoteStream( Stream Function() createStream, SendPort port) { Future<void> runStreamSendEvents() async { try { await for (var event in createStream()) { // Send events on port. port.send([event]); } } catch (e, s) { // Send events on port. port.send([e, s]); } } return runStreamSendEvents; } // Example use: void main() async { await for (var v in runStream(() => someInts(5))) { print(v); } } Stream<int> someInts(int n) async* { for (var i = 0; i < n; i++) { yield i; } }There's value in keeping the sample as-is, using primitives, rather than replacing it. Using primitives without run is still a use case, even if this particular solution can be modified with run, it's still good to maintain a large example of primitive usage. So maybe another sample can be created, that just shows the same solution written with run.