Dart is too fast -

i'm trying understand why code print "check" twice...

import 'dart:io'; import 'dart:async'; import 'dart:convert';  future<map> ft_get_data() {   file data;    data = new file("data.json");   return data.exists().then((value) {     if (!value) {       print("data no exist...\ncreating file...");       data.createsync();       print("filling it...");       data.openwrite().write('{"index":{"content":"helllo"}}');       print("operation finish");     }   }).then((_) => data.readasstring()).then((content) => json.decode(content)       ).catcherror((e) => new map()); }  void main() {   map params;   string name;   num check = 0;    httpserver.bind('127.0.0.1', 8080).then((server) {     print("server lauching... $server");     server.listen((httprequest request) {       request.response.statuscode = httpstatus.accepted;       request.response.headers.contenttype = new contenttype('text', 'htm    l');       params = request.uri.queryparameters; // http://127.0.0.1:8080/?name=tristan       ft_get_data().then((data_map) {         name = data_map['index']['content'];         print('check: $check');         if (data_map.isnotempty) request.response.write(name); else             request.response.write('booh');         check++;       }).whencomplete(request.response.close);     });   }).catcherror((error) {     print("an error : $error.");   }); } 

is fast ? or there exist method make pause ? thank you.

i tried code , prints 0.

what client using access server?