Function mib 

pub const fn mib(n: usize) -> usize

Multiply by 1024² to express a byte count in mebibytes (MiB).

Returns usize; use mib_u64 when you need a u64.

use rama_utils::octets::mib;
const LIMIT: usize = mib(2);
assert_eq!(LIMIT, 2 * 1024 * 1024);