XKTLS_SESSION_IV_BUF_LEN
memcpy(&xk->iv, &ktls->params.iv, XKTLS_SESSION_IV_BUF_LEN);
memset(&xk->iv, 0, XKTLS_SESSION_IV_BUF_LEN);
uint8_t iv[XKTLS_SESSION_IV_BUF_LEN];