code: @SuppressWarnings("ResultOfMethodCallIgnored") void updateDestinationFilePath(String filename) {
      String separator = destinationDirectory.endsWith("/") ? "" : File.separator;
      destinationFilePath = destinationDirectory + separator + filename;
      Log.d("TAG", "destinationFilePath: " + destinationFilePath);
      /* if the destination path is directory */
      File file = new File(destinationFilePath);
      if (!file.getParentFile().exists()) {
        /* make dirs in case */
        file.getParentFile().mkdirs();
      }
    }
docs: Update absolute file path according to the directory and filename.
  
  @param filename filename to save