Function addmul_n 

pub fn addmul_n(lhs: &mut [u64], a: &[u64], b: &[u64])

⚠️ Computes wrapping result += a * b, with a fast-path for when all inputs are the same length and small enough.

⚠️ This function is not part of the stable API.

See [`addmul`] for more details.