public Session start(SessionContext context) {
        Session session = createSession(context);
        applyGlobalSessionTimeout(session);
        onStart(session, context);
        notifyStart(session);
        //Don't expose the EIS-tier Session object to the client-tier:
        return createExposedSession(session, context);
    }
Publishes events on the event bus if the event bus is non-null, otherwise does nothing.

@param event the event to publish on the event bus if the event bus exists.
@since 1.3
core/src/main/java/org/apache/shiro/session/mgt/AbstractNativeSessionManager.java