splaying

Hi Sensuite:

I'd like each node to check our graphite server to determine if its CPU steal percent merited a warning. Of course, when I tried it, that generated a thundering herd when the sensu server published a check request. I was doing this because the check_cpu.rb plugin has steal/usage that are 10x what we get from collectd (or what I observe w/ top).

I can re-implement as a standalone check with some sort of randomization around the interval, but I prefer most checks regarding node health to come from the server.

From https://github.com/sensu/sensu/blob/master/lib/sensu/client.rb#L221 it looks like one could add a random splay to `scheduling_delay` without too much hackery, but that may be undesirable.

So this brings me to the following questions:
* Is there a current method to splay the client scheduling of checks?
* Would adding splay be an acceptable feature?
* Am I just wrongheaded about this?
* (and why does check_cpu.rb give such inflated results)?

-Peter B