public T getLast() {
		if (tree.isEmpty()) {
			return null;
		}
		Integer key = tree.lastKey();
		LinkedList<T> list = tree.get(key);
		return list.getLast();
	}
Returns the object with the highest priority number in the queue.
If more than one object has the same priority, then the object that
was added to the queue last is considered to have the higher priority value.
Null is returned if the queue is empty.
Ghidra/Framework/Generic/src/main/java/ghidra/util/datastruct/PriorityQueue.java