anchor.diff:    print(formattedMessage);
   }
   
  -String _getHostname() =>
  -    (Process.runSync('/bin/hostname', []).stdout as String).trim();
  -
   class AppEngineHttpServer {
     final ContextRegistry _contextRegistry;
   
     final String _hostname;
     final int _port;
   
  -  final String _localHostname;
     final Completer _shutdownCompleter = new Completer();
     int _pendingRequests = 0;
   
  
positive.code: 
          _pendingRequests++;
          var context = _contextRegistry.add(appengineRequest);
          /*
           * This sets the 'Server' header in the http response to the hostname
           * of the machine the application is running on.
           * It seems like the AppEngine VmRuntime stub (on the other end) will
           * not accept the response if we use the default value.
           */
          appengineRequest.response.headers.set('Server', _localHostname);
          appengineRequest.response.registerHook(
              () => _contextRegistry.remove(appengineRequest));
  
  
negative.code: 
    AppEngineHttpServer(this._contextRegistry,
                        {String hostname: '0.0.0.0', int port: 8080})
        : _hostname = hostname, _port = port;
  
    Future get done => _shutdownCompleter.future;
  
  