docs: public void addFile(File file) throws IOException {
  		if (!file.exists()) {
  			throw new IllegalArgumentException(String.format("File |%s| does not exist.", file));
  		}
  		if (file.isDirectory()) {
  			throw new IllegalArgumentException(String.format("File |%s| is a directory.", file));
  		}
  		addFileEntry(file.getPath(), new FileInputStream(file));
  	}