anchor.diff:  \tport\tdefault: $port""";
   
   Map<String, String> data = new Map<String, String>();
  +Map<String, Completer> changeFutures = new Map<String, Completer>();
   
   main(List<String> args) async {
     try {
  
positive.code: setData(key, value) async {
    print("\t" + key + " ← " + value);
    data[key] = value;
    await new File(persistanceFileName).writeAsString(JSON.encode(data));
  }
  
  
negative.code: import 'dart:async';
  import "dart:convert";
  import 'dart:io';
  
  