default Stream<? extends Ticket> stream(final TicketRegistryStreamCriteria criteria) {
        return getTickets().parallelStream();
    }
Gets tickets stream.
<p>
The returning stream may be bound to an IO channel (such as database connection),
so it should be properly closed after usage.

@return the tickets stream
api/cas-server-core-api-ticket/src/main/java/org/apereo/cas/ticket/registry/TicketRegistry.java