@Override
	public boolean hasNext() throws CancelledException {
    	monitor.checkCancelled();
		return !blockRefQueue.isEmpty();
    }
@see ghidra.program.model.block.CodeBlockReferenceIterator#hasNext()
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/block/SimpleDestReferenceIterator.java