pub unsafe extern "C" fn wc_HKDF(
    type_: c_int,
    inKey: *const byte,
    inKeySz: word32,
    salt: *const byte,
    saltSz: word32,
    info: *const byte,
    infoSz: word32,
    out: *mut byte,
    outSz: word32
) -> c_int