custom event is public because otherwise there's no point at all
Gets the specific event instance. First, check the type (such as in a switch statement), then extract the correct one from here. Note that the template argument is a value type of the enum above, not a type argument. So to use it, do event.get!(InputEvent.Type.KeyboardEvent), for example.
Returns a pointer to the terminal associated with this event. (You can usually just ignore this as there's only one terminal typically.)