https://stackoverflow.com/questions/55018479/offsets-are-different-ontap-and-ondrag-flutter


https://pub.dev/packages/dio#examples


class ServerProxy
{
  Dio dio;

  Singleton._privateCtor() {

    BaseOptions options = new BaseOptions(
        baseUrl: "https://www.xx.com/api",
        connectTimeout: 5000,
        receiveTimeout: 3000,
    );

    dio = Dio(options);
  }


  static final ServerProxy _singleton = ServerProxy._privateCtor();

  factory ServerProxy() => _singleton;


  String getAsTextEndPoint = "/getAsText";
  Future<String> getAsText(Image img) {
    FormData formData = FormData.from({
        "file": await MultipartFile.fromFile(IDK_WHAT_TO_PUT_HERE, filename: "upload.txt") //TODO
    });
    Response response = await dio.post(
      getAsTextEndPoint,
      data: formData
      onSendProgress: (int sent, int total) { //TODO
        print("$sent $total");
      }
    );

    int statusCode = response.statusCode;
    const int SUCCESS_CODE = 123 //TODO

    if(statusCode != SUCCESS_CODE)
      throw("request unsuccessfu! [STATUS CODE: $statusCode");

    return response.data.toString();
  }

}