Make the repeating argument to timers optional.

samples/chat/chat_server.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #library("chat_server.dart");
 #import("chat_server_lib.dart");
 
 
 final DEFAULT_PORT = 8123;
 final DEFAULT_HOST = "127.0.0.1";
 
 void main() {
   // For profiling stopping after some time is convenient. Set
   // stopAfter for that.
   int stopAfter;
 
   ServerMain serverMain =
       new ServerMain.start(new ChatServer(), DEFAULT_HOST, DEFAULT_PORT);
 
   // Start a shutdown timer if requested.
   if (stopAfter != null) {
-    new Timer((timer) => serverMain.shutdown(), stopAfter * 1000, false);
+    new Timer((timer) => serverMain.shutdown(), stopAfter * 1000);
   }
 }