anchor.diff:  class ServerWorker {
     final int id;
     final SendPort port;
  -  
  +
     ServerWorker(this.id, this.port);
  -  
  +
     ReceivePort recv;
     Stream receiver;
  -  
  +
     init() async {
       recv = new ReceivePort();
       receiver = recv.asBroadcastStream();
       sleep(new Duration(milliseconds: 2));
       port.send(recv.sendPort);
     }
  -  
  +
     void send(value) => port.send(new WorkerMessage(id, value));
   }
   
   class WorkerMessage {
     final int id;
     final dynamic value;
  -  
  +
     WorkerMessage(this.id, this.value);
   }
   
   runWorker(ServerWorker worker) async {
     await worker.init();
  -  
  +
     var server = await HttpServer.bind("0.0.0.0", 8080, shared: true);
  -  
  +
     await for (var request in server) {
       print("[Worker ${worker.id}] ${request.method} ${request.uri.path} (${request.connectionInfo.remoteAddress.address})");
       
  -    var path = request.uri.path;
  -    
  -    if (path == "/") {
  -      path = "/index.html";
  -    }
  -    
  -    path = path.substring(1);
  -    
  -    var file = new File(path).absolute;
  -    var dir = new Directory(path).absolute;
  -    
  -    if (await dir.exists() || (file.path.endsWith("/index.html") && !(await file.exists()))) {
  -      dir = new Directory(dir.path.replaceAll("index.html", ""));
  -      
  -      path = path.replaceAll("index.html", "/");
  -      
  -      if (path[0] != "/") {
  -        path = "/" + path;
  -      }
  -      
  -      var list = LISTING.replaceAll("{path}", path).replaceAll("{files}", (await dir.list().toList()).map((entity) {
  -        var m = entity.path.replaceAll(dir.path, "");
  -        
  -        if (entity is Directory) {
  -          m += "/";
  -        }
  -        
  -        var out = '<li><a href="${m}">${m}</a></li>';
  -        
  -        return out;
  -      }).join());
  -      request.response.headers.contentType = ContentType.HTML;
  -      request.response
  -        ..writeln(list)
  -        ..close();
  -      continue;
  -    }
  -    
  -    if (!(await file.exists())) {
  -      request.response
  -              ..statusCode = 404
  -              ..writeln("Not Found")
  -              ..close();
  -      continue;
  -    }
  -    
  -    for (var ext in MIMES.keys) {
  -      if (file.path.endsWith(ext)) {
  -        request.response.headers.contentType = ContentType.parse(MIMES[ext]);
  -      }
  -    }
  -    
  -    file.openRead().pipe(request.response).then((_) => request.response.close());
  +    await serveFile(request, request.response);
     }
   }
   
  
positive.code:   var recv = new ReceivePort();
    var receiver = recv.asBroadcastStream();
    var senders = <int, SendPort>{};
    
    for (var i = 1; i <= workers; i++) {
      await Isolate.spawn(runWorker, new ServerWorker(i, recv.sendPort));
      print("[Worker ${i}] Spawned.");
      senders[i] = await receiver.first;
    }
  }
  
negative.code: import "dart:async";
  import "dart:convert";
  import "dart:io";
  import "dart:isolate";
  
  const int workers = 3;
  const UNSPECIFIED = const Object();
  const String LISTING = """
  