Mechanism to control the agent heart beat interval.

From http://forums.atlassian.com/thread.jspa?messageID=257276351#257276351

Just wondering - is there also a way to control the heartbeat time? It looks like the heartbeat pings the server every second or so. If this was a configurable option (to adjust it to every 2 minutes or 30 minutes, etc.) that would be great. I imagine I will have a lot of agents and this would just cut down on all the network chatter. I've poked around a bit in the admin pages and config files, and maybe it there, but I missed it.