l0rinc

@luke-jr, would this optimization be more welcome in https://github.com/bitcoin/libbase58 instead?

@josibake, now that the cherry-pick was merged, I've rebased and re-measured - the important part of this change was already included in the other PR, the remaining optimizations here are...

Thanks for the reviews @josibake, @sipa, @achow101. There's a similar small optimization for [transaction input/output allocations](https://github.com/bitcoin/bitcoin/pull/30093) as well, I'd appreciate a review.

How do you imagine it being done, since we can't just insert a try/catch around the constructor body?

Any progress with unmodifable collection support for Kryo5?

Could you add an example on how to do that exactly? We ended up reimplementing all the unmodifable collection serializers for Kryo 5.

We depend on both version of Kryo, so we're getting: 

ACK 57a06646952fed98c1c281f02fe58a0758a8ed5a

re-ACK 9408a04e424cee0d226bde79171bd4954f9caeb0

ACK e41667b720372dae8438ea86e9819027e62b54e0 Great job, love the results of these untangling tasks!