private static void queueDestReferences(List<CodeBlockReference> blockRefQueue, CodeBlock srcBlock, Address srcAddr, Address destAddr, FlowType flowType) {
    	if (blockRefQueue != null) {			
	        CodeBlockReference blockRef = new CodeBlockReferenceImpl(
	        										srcBlock,
	        										null,
	        										flowType, 
	        										destAddr, 
	        										srcAddr);
			blockRefQueue.add(blockRef);
    	}
    }
Create destination block reference(s) and add to the blockRefQueue if not null.
A valid CodeBlock must exist at the destAddr for a reference to be added and/or counted.
@param blockRefQueue the CodeBlockReference queue, may be null
@param srcBlock the source block associated with the CodeBlockReference(s)
@param srcAddr source address
@param destAddr destination address
@param flowType the flow type to be associated with reference.
@return the number of destination references
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/block/SubroutineDestReferenceIterator.java