1. An apparatus operating on a time sequence of events, the apparatus comprising: an event handling module configured to generate a predicted label for a current observed event of the time sequence of events; and a true label handling module configured to process a true label revealed for an observed event of the time sequence of events; wherein the event handling module and the true label handling module operate asynchronously, are embodied by one or more digital processors, and cooperatively model stochastic dependence of a true label for the current observed event based on observed events of the time sequence of events and any true labels revealed for r past observed events of the time sequence of events.