presto-plugin-toolkit/src/main/java/io/prestosql/plugin/base/authentication/KerberosTicketUtils.java/KerberosTicketUtils/getRefreshTime
class KerberosTicketUtils:    public static long getRefreshTime(KerberosTicket ticket)
    {
        long start = ticket.getStartTime().getTime();
        long end = ticket.getEndTime().getTime();
        return start + (long) ((end - start) * TICKET_RENEW_WINDOW);
    }