fn from_u64(x: u64) -> u32 {
        (((((x >> 31) + x + 1) >> 31) + x) & (MERSENNE_31_PRIME_FIELD_ORDER as u64)) as u32
    }
Returns the element `x * 1` where 1 is the multiplicative neutral element.
crates/math/src/field/fields/mersenne31/field.rs