private void cachePair(Long srcKey, Long destKey, NeighborhoodPair pair) {
		PairLabel newLabel = new PairLabel();
		newLabel.srcLabel = srcKey;
		newLabel.destLabel = destKey;
		namespacePair.put(newLabel, pair);
	}
A neighborhood generator that, for a given function, generates all functions
in the same namespace.  For efficiency, it caches the namespace sets it generates.
Ghidra/Features/VersionTrackingBSim/src/main/java/ghidra/feature/vt/api/NamespaceNeighborhood.java