With this WIP Milhouse PR we can measure the exact size of the state cache in memory:

• Add differential memory usage tracking milhouse#51

That PR needs a bit more work to handle nested lists etc (for full generality), and possibly some API improvements to make it less error-prone.

I had a PoC PR to implement the state cache size in Lighthouse which we can revive once the Milhouse feature itself is ready:

• State cache memory size WIP #6532