docs: void renameTempFile(FileExtension extension) {
      String fileName = filenameForUrl(url, extension, true);
      File file = new File(appContext.getCacheDir(), fileName);
      String newFileName = file.getAbsolutePath().replace(".temp", "");
      File newFile = new File(newFileName);
      boolean renamed = file.renameTo(newFile);
      L.debug("Copying temp file to real file (" + newFile + ")");
      if (!renamed) {
        L.warn( "Unable to rename cache file " + file.getAbsolutePath() + " to " + newFile.getAbsolutePath() + ".");
      }
    }