In HUDService.startHTTPObservation() the httpObserver builds an httpActivity object and a loggedNode object coming from the HUDService.messageFactory() method.
The messageFactory() takes as input the httpActivity object and returns a messageObject that holds the activityObject property as a reference back to the httpActivity object. Then we have the httpObserver which sets httpActivity.messageObject = loggedNode.
A cyclic reference only spells trouble ahead. We should fix this.
Not sure if this has actually caused any problems, investigation needed.
This is likely to be fixed by the patch of bug 673148