Progress: Continue adding FSS Payload processing code.

Progress: Continue adding FSS Payload processing code.

I decided to use two caches.
One for the main cache.
The other for a smaller, multi-purpose cache.

The second cache should be smaller and so re-allocations should be cheaper.
Use re-allocations on this as much as possible.

There are some code changes that I was indecisive around and jumped around on implementation.
I think I cleaned that all up but I may have missed something.