An event object is an encapsulation of a Simics event that can be posted on a processor time or step queue. The location of event objects in the object hierarchy of the device is not important, so an event object can generally be placed wherever it is most convenient.
An event has a built-in post method, which inserts the event in the default queue associated with the device. When the event is triggered, the event method of the event is called. The built-in default event method simply logs that the event has occurred, which can be useful for testing purposes.