Hi,
I'm playing with partial object's state transfer, similar to how
AtomicHashMap/AtomicHashMapDelta works. The purpose of these classes is,
among other things, to show that for objects large in size we can
transfer just the updated part of them, not whole objects.

I tried to implement DeltaAware and Delta interfaces and my tests showed
that only methods of the delta object's externalizer were called. Not
methods of the externalizer of the actual object holding the data.

To be precise - I have two classes:
Bicycle implements DeltaAware (similar to AtomicHashMap)
BicycleDelta implements Delta (similar to AtomicHashMapDelta)

...and only BicycleDelta's externalizer's methods were called. Not those
of Bicycle's externalizer.

This brings me to AtomicHashMap... is the externalizer for this class
ever used/needed?