Added support for async task immediate priority

Change-Id: Ie7e48b23a468844adca1e02a460eff55d4c619fc
simplified code, taking advantage of new automatic unbusy trigger

Change-Id: Ie3243180599732ff7d546aff9311e994a6568c22
now using async task w/ immediate priority for unbusy trigger

Change-Id: I63598d67a0a0dfdd9f3cb0e523390e0b6d72d75e