#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub enum Overflow {
Arena { left: usize, right: usize },
Index { left: usize, right: usize },
Resident { left: usize, right: usize },
Allocations { left: usize, right: usize },
Tail { left: usize, right: usize },
}
const _: () = assert!(size_of::<Overflow>() == 3 * size_of::<usize>());