[okio_3_2_0]: https://square.github.io/okio/changelog/#version-320
[okio_3_7_0]: https://square.github.io/okio/changelog/#version-370
[okio_3_9_0]: https://square.github.io/okio/changelog/#version-390
[rfc_8305]: https://tools.ietf.org/html/rfc8305
[startup_1_2_0]: https://developer.android.com/jetpack/androidx/releases/startup#1.2.0
[uts46]: https://www.unicode.org/reports/tr46
[zstd]: https://github.com/facebook/zstd

     *
     * @param filter the LDAP search filter to escape (null is treated as empty string)
     * @return the escaped filter string safe for use in LDAP queries (empty string if filter is null)
     * @see <a href="https://tools.ietf.org/html/rfc4515">RFC 4515 - LDAP String Representation of Search Filters</a>
     */
    protected String escapeLDAPSearchFilter(final String filter) {
        if (filter == null) {
            return "";
        }