Individual samples do not in any significant sense constitute events. The only thing that really pays them any attention is metering, and the result of that process is only displayed to the user periodically (i.e. something roughly equivalent to the screen refresh rate).
Even higher level objects, such as what are various called "clips" or "regions" or "events" frequently pay no role in any type of event notification system. In some designs, the boundaries of such objects may play a somewhat event-like fole.