anchor.diff:    var senders = <int, SendPort>{};
     
     for (var i = 1; i <= workers; i++) {
  -    var isolate = await Isolate.spawn(worker, new ServerWorker(i, recv.sendPort));
  +    await Isolate.spawn(runWorker, new ServerWorker(i, recv.sendPort));
       print("[Worker ${i}] Spawned.");
       senders[i] = await receiver.first;
     }
  -  
  -  runDatabase(receiver, senders);
   }
  -
  -class DatabaseRequest {
  -  final String key;
  -  final dynamic value;
  -  
  -  DatabaseRequest(this.key, [this.value = UNSPECIFIED]);
  -  
  -  bool get isGetRequest => value == UNSPECIFIED;
  -  bool get isSetRequest => value != UNSPECIFIED;
  -}
  -
  -class DatabaseResponse {
  -  final String key;
  -  final dynamic value;
  -  
  -  DatabaseResponse(this.key, [this.value = UNSPECIFIED]);
  -  
  -  bool get isGetResponse => value != UNSPECIFIED;
  -  bool get isSetResponse => value == UNSPECIFIED;
  -}
  -
  -class WorkerMessage {
  -  final int id;
  -  final dynamic value;
  -  
  -  WorkerMessage(this.id, this.value);
  -}
  -
  -runDatabase(ReceivePort receiver, Map<int, SendPort> senders) async {
  -  var storage = <String, dynamic>{
  -    "test": 1
  -  };
  -  
  -  await for (var m in receiver) {
  -    var port = senders[m.id];
  -    var message = m.value;
  -    
  -    if (message is DatabaseRequest) {
  -      if (message.isGetRequest) {
  -        port.send(new DatabaseResponse(message.key, storage[message.key])); 
  -      } else if (message.isSetRequest) {
  -        storage[message.key] = message.value;
  -        port.send(new DatabaseResponse(message.key));
  -      }
  -    }
  -  }
  -}
positive.code:   init() async {
      recv = new ReceivePort();
      receiver = recv.asBroadcastStream();
      sleep(new Duration(milliseconds: 500));
      port.send(recv.sendPort);
    }
    
    get(String key) async {
      send(new DatabaseRequest(key));
      
      return (await receiver
          .where((it) => it is DatabaseResponse && it.isGetResponse && it.key == key)
          .first).value;
    }
    
    set(String key, value) async {
      send(new DatabaseRequest(key, value));
      
      return (await receiver
          .where((it) => it is DatabaseResponse && it.isSetResponse && it.key == key)
          .first).value;
    }
    
    void send(value) => port.send(new WorkerMessage(id, value));
  }
  
  worker(ServerWorker w) async {
    await w.init();
    
    var server = await HttpServer.bind("0.0.0.0", 8080, shared: true);
    
    await for (var request in server) {
      print("[Worker ${w.id}] ${request.method} ${request.uri.path} (${request.connectionInfo.remoteAddress.address})");
      
      if (request.uri.path == "/") {
        var number = await w.get("test");
        number++;
        await w.set("test", number);
        request.response
          ..writeln("Worker ${w.id} says hello! (${number})")
          ..close();
      } else {
        request.response
          ..statusCode = 404
          ..writeln("Not Found")
          ..close();
      }
    }
  }
  
  
negative.code: import "dart:async";
  import "dart:io";
  import "dart:isolate";
   
  const int workers = 3;
  const UNSPECIFIED = const Object();
  const String LISTING = """
  <!DOCTYPE html>
  <html>
    <title>Directory listing for {path}</title>
    <body>
      <h2>Directory listing for {path}</h2>
      <hr>
        <ul>{files}</ul>
      <hr>
    </body>
  </html>
  """;
  
  const Map<String, String> MIMES = const {
    ".html": "text/html",
    ".txt": "text/plain",
    ".css": "text/css",
    ".js": "application/js",
    ".dart": "application/dart",
    ".json": "application/json",
    ".xml": "text/xml"
  };
  
  class ServerWorker {
    final int id;
  