public SessionStorageEvaluator getSessionStorageEvaluator() {
        return sessionStorageEvaluator;
    }
Returns the {@code SessionStorageEvaluator} that will determine if a {@code Subject}'s state may be persisted in
the Subject's session.  The default instance is a {@link DefaultSessionStorageEvaluator}.

@return the {@code SessionStorageEvaluator} that will determine if a {@code Subject}'s state may be persisted in
the Subject's session.
@see DefaultSessionStorageEvaluator
core/src/main/java/org/apache/shiro/mgt/DefaultSubjectDAO.java