We could in theory actually support this case by throwing a Promise when
it's used inside a render. Allowing it to be synchronously unwrapped.
However, it's a bit sketchy because we officially only support this in
the render's child position or in `use()`.
Another alternative could be to actually pass the Promise/Lazy to the
callback so that you can reason about it and just return it again or
even unwrapping with `use()` - at least for the forEach case maybe.
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