public Integer getFirstPriority() {
		if (tree.isEmpty()) {
			return null;
		}
		Integer key = tree.firstKey();
		return key;
	}
Returns the priority of the object with the lowest priority in the queue.
Null returned if the queue is empty.
Ghidra/Framework/Generic/src/main/java/ghidra/util/datastruct/PriorityQueue.java