public int getErrCode() {
        return errCode;
    }
@Test
    void testConstructorWithErrorCode() {
        NacosRuntimeException exception = new NacosRuntimeException(NacosException.INVALID_PARAM);
        assertEquals(NacosException.INVALID_PARAM, exception.getErrCode());
        assertNull(exception.getMessage());
        assertNull(exception.getCause());
    }