anchor.diff:        (request, response) {
       response.statusCode = 400;
       response.contentLength = 0;
  -    response.outputStream.close();
  +    closeResponse(request, response);
     });
   
     _server.addRequestHandler((request) => request.path == '/loop',
  
positive.code:     response.headers.set('location',
          serverUrl.resolve('/loop?${n + 1}').toString());
      response.contentLength = 0;
      response.outputStream.close();
    });
  
    _server.addRequestHandler((request) => request.path == '/redirect',
  
negative.code: void stopServer() {
    _server.close();
    _server = null;
  }
  
  /// Closes [response] while ignoring the body of [request].
  ///
  /// Due to issue 6984, it's necessary to drain the request body before closing
  /// the response.
  void closeResponse(HttpRequest request, HttpResponse response) {
    request.inputStream.onData = request.inputStream.read;
    request.inputStream.onClosed = response.outputStream.close;
  }
  
  /// A matcher that matches JSON that parses to a value that matches the inner
  