stable version 1 that made an index only when a flush was constructed
   at [1]https://lists.cpunks.org/pipermail/cypherpunks/2022-July/102291.h
   tml
   attached wip version is behaving consistently and retains a running
   index updated every write, but makes less optimized trees because i
   have not implemented branch merging or making branches shallower when
   they get skinnier, and am using recursion and excessive heap
   construction to shorten the implementation for my confused mind.
   I seem to have more inhibition when I try to make dependecy components
   with suites of methods. very hard to reuse these. so I redid it a
   different way. Just implemented write merging.

References

   1. https://lists.cpunks.org/pipermail/cypherpunks/2022-July/102291.html