库“dart:isolate”中是否有 dart 的 `spawnUri(...)` 示例？

有一个spawnUri(uri)函数于dart:isolate，但我没有找到任何例子。我猜到了它的用法，但失败了。

假设有2个文件，在第一个文件中，它会调用spawnUri对于第二个，并与之沟通。

首先.dart

import "dart:isolate";

main() {
  ReceivePort port = new ReceivePort();
  port.receive((msg, _) {
    print(msg);
    port.close();
  });
   var c = spawnUri("./second.dart");
   c.send(["Freewind", "enjoy dart"], port.toSendPort());
}

第二个.dart

String hello(String who, String message) {
   return "Hello, $who, $message";
}

void isolateMain(ReceivePort port) {
  port.receive((msg, reply) => reply.send(hello(msg[0], msg[1]));
}

main() {}

但这个例子不起作用。我不知道正确的代码是什么，如何解决？

这是一个适用于 Dart 1.0 的简单示例。

应用程序.dart：

import 'dart:isolate';
import 'dart:html';
import 'dart:async';

main() {
  Element output = querySelector('output');

  SendPort sendPort;

  ReceivePort receivePort = new ReceivePort();
  receivePort.listen((msg) {
    if (sendPort == null) {
      sendPort = msg;
    } else {
      output.text += 'Received from isolate: $msg\n';
    }
  });

  String workerUri;

  // Yikes, this is a hack. But is there another way?
  if (identical(1, 1.0)) {
    // we're in dart2js!
    workerUri = 'worker.dart.js';
  } else {
    // we're in the VM!
    workerUri = 'worker.dart';
  }

  int counter = 0;

  Isolate.spawnUri(Uri.parse(workerUri), [], receivePort.sendPort).then((isolate) {
    print('isolate spawned');
    new Timer.periodic(const Duration(seconds: 1), (t) {
      sendPort.send('From app: ${counter++}');
    });
  });
}

工人.dart：

import 'dart:isolate';

main(List<String> args, SendPort sendPort) {
  ReceivePort receivePort = new ReceivePort();
  sendPort.send(receivePort.sendPort);

  receivePort.listen((msg) {
    sendPort.send('ECHO: $msg');
  });
}

构建过程分为两步：

1. pub build
2. dart2js -m web/worker.dart -obuild/worker.dart.js

在这里查看完整的项目：https://github.com/sethladd/dart_worker_isolates_dart2js_test