ossl_json_str_len
void ossl_json_str_len(OSSL_JSON_ENC *json, const char *str, size_t str_len);
ossl_json_str_len(&qlog->json, value, value_len);
#define OPJ_STR_LEN(x, xl) OP_CALL_PZ(ossl_json_str_len, (x), (xl))