CBS_peek_last_u8
int CBS_peek_last_u8(CBS *cbs, uint8_t *out);
if (!CBS_peek_last_u8(cbs, &octet))
if (!CBS_peek_last_u8(&cbs, &octet))
if (!CBS_peek_last_u8(&cbs, &octet))
int CBS_peek_last_u8(CBS *cbs, uint8_t *out);