void main() {
  v('verbose message');
  d('debug message');
  i('info message');
  w('warning message');
  e('error message');
  wtf('wtf message');
}

void main() {
  // init logger with dir. then all logs will be saved to this dir.
  await initLogger(
    '/tmp/app_log_files_dir',
    maxFileCount: 10, // max 10 files.
    maxFileLength: 5 * 1024 * 1024, // max to 5 MB for single file.
  );
  i('after initLogger');
}