This removes quite a bit of work, and work that was difficult to reason
about. While I'm disappointed that that hard work is lost (aside from
digging it up in the commit history), I am happy that it was able to be
removed, because the extra complexity and cognitive burden was significant.
This removes more `memcpy`s than the sum state could have hoped to, since
aggregation is no longer necessary. Given that, there is a slight
performacne improvement. The re-introduction of required and duplicate
checks later on should be more efficient than this was, and so this should
be a net win overall in the end.
DEV-13346