anchor.diff:  
             return new HttpClient().get('localhost', server.port, '/file')
                 .then((request) => request.close())
  -              .then((response) => response.statusCode)
  +              .then((response) => response.drain().then(
  +                  (_) => response.statusCode))
                 .whenComplete(() {
                   server.close();
                   dir.deleteSync();
  
positive.code: 
            return new HttpClient().get('localhost', server.port, '/dir/file')
                .then((request) => request.close())
                .then((response) => response.statusCode)
                .whenComplete(() {
                  server.close();
                  file.deleteSync();
  
negative.code: 
            return new HttpClient().get('localhost', server.port, '/file')
                .then((request) => request.close())
                .then((response) => response.drain().then(
                    (_) => response.statusCode))
                .whenComplete(() {
                  server.close();
                  file.deleteSync();
  