Enum All Roles in a Principal?

From: localhost (primpilus_at_cohort.ces)
Date: 02/27/04 

Date: Fri, 27 Feb 2004 11:52:31 -0500

I know how to do ..IsInRole() to test if a user is in a particular
role.

How do I enumerate all of the roles currently attached to my principal
instance? WindowsPrincipal or GenericPrincipal.

Thanks.