before, cache would clone the underlying object every time it was
accessed. this was definitely incredibly wasteful! now it clones the
Arc, which is super cheap. the extra work necessary while fetching
things is most likely more than compensated by saved clones every time
we render stuff. there is some dumb arc creation here and there (like
for the debug page), but it's mostly my lazyness, they can probably go
and should not be that much of a big deal anyway.
TLDR things were already fast but should be EVEN FASTER!!!
