private NeighborhoodPair findPair(Long srcKey, Long destKey) {
		cacheKey.srcLabel = srcKey;
		cacheKey.destLabel = destKey;
		return namespacePair.get(cacheKey);
	}
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