Additional information in plugin hook? (no replies)

In /core/Tracker/Action.php there is this code:

Piwik_PostEvent('Tracker.Action.record', $this, $info);

It passes as notification the Action object, and some additional information in $info.
When I use it in the plugin, I have;

$this->action_info =& $notification->getNotificationObject();

This gives me the Action object. How do I access the $info too?