`memcpy()` and `memmove()` are functionally equivalent if the source and
destination memory regions do not overlap. If this is the case, we
should prefer `memcpy()` as it's implemented in a simpler and faster
way. As our `memcpy()` starts copying from the lowest address first,
relaxing a `memmove()` call to `memcpy()` is safe if the destination:
- starts at a lower address than the source
- starts at a higher address than the source's end
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