1. A processing system, comprising a state machine defined by a plurality of states and event-dependent transitions therebetween, and including an inference engine configured to permit inference of likely completion of one or more missed event inputs to said state machine from observation of successful completion of an out-of-order event, and to allow said state machine to proceed to a new one of said states associated with said successful completion of said out-of-order event from a current one of said states in the absence of said missed event inputs.