Function kdf_hash_length

pub fn kdf_hash_length<H>(
    key: &[u8],
    label: &str,
    context: &[u8],
    bits: usize,
) -> Vec<u8> 
where
    H: Hasher,
    <<H as Hasher>::Digest as Digest>::Bytes: AsRef<[u8]> + AsMut<[u8]>,

IEEE Std. 802.11-2020 12.7.1.6.2 The KDF function (named “KDF-Hash-Length” in the specification).