).addPrefixPath(
                        "helloworld",
                        new HttpHandler(){
                            public void handleRequest(HttpServerExchange httpServerExchange) throws Exception {
                                Map<String, Deque<String>> parameters = httpServerExchange.getQueryParameters();
                                Optional<Deque<String>> nameParameters = Optional.ofNullable(parameters.get("name"));
                                String name = nameParameters.map(p -> p.peek()).orElse("");
                                httpServerExchange.getResponseHeaders().put(Headers.CONTENT_TYPE, "text/plain");
                                httpServerExchange.getResponseSender().send("Hello, ", new IoCallback() {
                                    @Override
                                    public void onComplete(HttpServerExchange httpServerExchange, Sender sender) {
                                        System.out.println("callback");
                                        sender.send(name);
                                    }

                                    @Override
                                    public void onException(HttpServerExchange httpServerExchange, Sender sender, IOException e) {
                                        System.out.println(e);
                                    }
                                });
                            }
                        }