How to restore subscriber's session when server is restarted?

Hi,

I used activemq 5.8.0 with mqtt( http://activemq.apache.org/mqtt.html
<http://activemq.apache.org/mqtt.html> )

If the subscriber is offline and there is session then the pending messages
could be increased when the publisher sent the message.

But activemq server is restarted then the subscriber's session is out.
So there are no pending messages when the publisher sent the message.

I want to restore the subscriber's session when server is restarted.

Thanks