* @param scope cache scope
     * @return lease key or null if not supported
     * @throws SmbException if an error occurs
     */
    public static Smb2LeaseKey requestDirectoryLease(SmbFile smbFile, int requestedState, DirectoryCacheScope scope) throws SmbException {
        if (!smbFile.isDirectory()) {
            throw new SmbException("Directory leasing only supported for directories");
        }