Function crypto_kdf_hkdf_sha256_expand 

pub fn crypto_kdf_hkdf_sha256_expand(
    output: &mut [u8],
    context: &[u8],
    prk: &HkdfSha256Key,
) -> Result<(), Error>

Expands an HKDF-SHA-256 pseudorandom key into output keying material.

Errors

Returns an error if output is outside the supported HKDF-SHA-256 output length range.