Function hkdf_expand

pub fn hkdf_expand<H>(prk: &[u8], info: &str, length: usize) -> Vec<u8> 
where
    H: Hasher,
    <<H as Hasher>::Digest as Digest>::Bytes: AsRef<[u8]>,

IEEE Std. 802.11-2020 12.4.4.2.3/12.4.4.3.3, IETF RFC 5869 A KDF to “expand” entropy into a long key (named “H” and “HKDF-Expand” in the specification).