ANDROID: how does addProximityAlert() work exactly?

I'm looking for information about how "addProximityAlert()" exactly works

At what intervals does it check? What happens if we use more than one addProximmityAlert(, do they work indepe开发者_StackOverflowndently(do they check individually)?

SDK documentation says only about interval when device is suspended (4 minutes) but does not about interval when device is awake so I suppose that it's "ok for most purposes".

Proximity alerts ar added to single HashMap (check this) so they are checked one by one for actual location.