# Register an `event` in the queue to be active in `delay` units of time.
	#
	# If `duration` is given, this is duration after what the event is automatically discarded.
	# If `null`, 0.0 or not given, the event will be executed only once
	# Use `inf` for an event with an infinite duration.
	fun add(event: E, delay: Float, duration: nullable Float): EventInfo[E]
	do
		return add_at(event, time + delay, duration)
	end