public Long getTimeToIdle() {
        return ticketGrantingTicket.getExpirationPolicy() instanceof final IdleExpirationPolicy iep ? iep.getTimeToIdle() : 0L;
    }
Get tgt's TTI.

@return tgt's TTI
api/cas-server-core-api-events/src/main/java/org/apereo/cas/support/events/ticket/AbstractCasTicketGrantingTicketEvent.java