private void layoutStateChanged(Event e) {
		if (!e.active) {
			// algorithm is done, release the latch
			taskDone.countDown();
		}
	}
Notification when the layout algorithm starts and stops
@param e the event. If the event.active is true, then the algorithm is starting, if false,
       the algorithm is done.
Ghidra/Features/GraphServices/src/main/java/ghidra/graph/visualization/SetLayoutTask.java