big_key_payload
struct big_key_payload *payload = to_big_key_payload(prep->payload);
struct big_key_payload *payload = to_big_key_payload(key->payload);
struct big_key_payload *payload = to_big_key_payload(key->payload);
struct big_key_payload *payload = to_big_key_payload(key->payload);
struct big_key_payload *payload = to_big_key_payload(key->payload);
(struct big_key_payload *)((payload).data)
struct big_key_payload *payload = to_big_key_payload(prep->payload);