pub unsafe fn to_bool(&self, position: usize) -> bool {
        let mask = 1 << position;
        mask & self.to_u64() == mask
    }
Interpreting the slot as a bitfield,
returns the bit at a given index.
If we have the bifield `0b10`, which is 5 decimal:
bit at position `0` is `0b0` is `false`,
bit at position `1` is `0b1` is `true`,
bit at positions `2..=64` are zeroed, so the rest are `false`.

# Safety
Caller must ensure that the slot in question is a bitfield.
passerine-qualm/src/slot.rs