pub unsafe extern "C" fn botan_pbkdf_timed(
    pbkdf_algo: *const c_char,
    out: *mut u8,
    out_len: usize,
    passphrase: *const c_char,
    salt: *const u8,
    salt_len: usize,
    milliseconds_to_run: usize,
    out_iterations_used: *mut usize
) -> c_int