anchor.diff:      });
   
       client = await completer.future;
  +
  +    var file = await credentialsFile.open(mode: FileMode.WRITE);
  +    await file.writeString(client.credentials.toJson());
  +    await file.close();
     }
   
  -  // Once you have a Client, you can use it just like any other HTTP
  -  var file = await credentialsFile.open(mode: FileMode.WRITE);
  -  await file.writeString(client.credentials.toJson());
  -  await file.close();
  -
  -  var result;
  -
  -  result = await client.read("https://passport.thegrid.io/api/user");
  -  print(result);
  -
  +  return client;
   }
  
positive.code:  * your TheGrid app to use your users credentials to perform API calls.
   * A callback will inform the application about the credentials and the
   * app will perform the actual API call.
  **/ 
  connect() async{
  
    final authorizationEndpoint =
    Uri.parse("https://passport.thegrid.io/login/authorize/");
    final tokenEndpoint =
    Uri.parse("https://passport.thegrid.io/login/authorize/token");
  
    // Fill in these values from your TheGrid app
    final identifier = "xxx";
    final secret = "xxx";
  
    final redirectUrl = Uri.parse("http://127.0.0.1:3000/");
  
  
negative.code:     var grant = new oauth2.AuthorizationCodeGrant(
          identifier, secret, authorizationEndpoint, tokenEndpoint);
  
      String authUrl = grant.getAuthorizationUrl(redirectUrl, scopes:["website_management", "content_management", "update_profile"]);
      print('Open browser and authenticate: ${authUrl}\n');
  
      HttpServer server = await HttpServer.bind(InternetAddress.LOOPBACK_IP_V4, 3000);
  
  