this quirk is left over from my strategies for making the loop off of
a previous loop:
# a stack to perform a depth-first enumeration of the tree
# atm, the offset is not updated as inner nodes are traversed. instead
# they are simply traversed again when backtracked, under the idea that
# total time is still O(log n)
# index stream offset index offset region size
indices = [(self.tail, 0, 0, total_size)]
Again, the O(log n) is something i hadn't written before, just a
nonverbal assumption i had while choosing design parts.
