This is a better measurement as if object self size is X and the
retainerSize Y. X will always be smaller then Y, there Y will be the
actual size on the Heap.
This refactors the code to extract the Id logic from the PageCollector
and provide it in the heapsnapshot.
We need to use an UID as we need the internal ClassKey to query the
heapsnapshot, but that is a strange string (usually looking like
`,ClassName`) which may get the LLM confused as we use comma separated
output.
Nikolay Vitkov