* @param url The URL.
     * @return The generated unique ID.
     */
    private String getId(final String sessionId, final String url) {
        final String id = sessionId + ID_SEPARATOR + new String(Base64.getUrlEncoder().withoutPadding().encode(url.getBytes(UTF_8)), UTF_8);
        if (id.length() <= idPrefixLength) {
            return id;
        }