crypto_digest_init
STRUCT_DECL(crypto_digest_init, digest_init);
rv = crypto_digest_init(mech, ctxp, NULL);
rv = crypto_digest_init(mech, ctxp, NULL);
rv = crypto_digest_init(mech, ctxp, NULL);
rv = crypto_digest_init(&mech, &ctxp, NULL);
extern int crypto_digest_init(crypto_mechanism_t *mech, crypto_context_t *ctxp,