// Save listing...
	go func() {
		if err := saver.saveMetaCacheStream(listCtx, &meta, saveCh); err != nil {
			meta.setErr(err.Error())
		}
		cancel()
	}()

	// Do listing...
	go func(o listPathOptions) {
		err := z.listMerged(listCtx, o, inCh)
		if err != nil {
			meta.setErr(err.Error())
		}
		o.debugln("listAndSave: listing", o.ID, "finished with ", err)
	}(*o)

	cancel context.CancelFunc
}

func (m *metaCacheRPC) setErr(err string) {
	m.mu.Lock()
	defer m.mu.Unlock()
	meta := *m.meta
	if meta.status != scanStateError {
		meta.error = err
		meta.status = scanStateError
	} else {
		// An error is already set.
		return
	}
	meta, _ = m.o.updateMetacacheListing(meta, m.rpc)
	*m.meta = meta
}

// getErr will return an error if the listing failed.

        data.setUrl(url);
        assertEquals(url, data.getUrl());

        data.setUrl(null);
        assertNull(data.getUrl());
    }

    public void test_httpStatusCodeGetterSetter() {
        // Test HTTP status code getter/setter
        ResponseData data = new ResponseData();

        data.setHttpStatusCode(200);
        assertEquals(200, data.getHttpStatusCode());

        data.setHttpStatusCode(404);

        // Test URL getter/setter
        UrlQueueImpl<Long> queue = new UrlQueueImpl<>();

        String url = "https://example.com/path";
        queue.setUrl(url);
        assertEquals(url, queue.getUrl());

        queue.setUrl(null);
        assertNull(queue.getUrl());
    }

    public void test_metaDataGetterSetter() {
        // Test metadata getter/setter
        UrlQueueImpl<Long> queue = new UrlQueueImpl<>();

    public void test_idGetterSetter() {
        // Test ID getter/setter
        AccessResultImpl<Long> result = new AccessResultImpl<>();

        result.setId(123L);
        assertEquals(Long.valueOf(123L), result.getId());

        result.setId(null);
        assertNull(result.getId());
    }

    public void test_sessionIdGetterSetter() {
        // Test session ID getter/setter

        // Test URL getter/setter
        RequestData data = new RequestData();

        String url = "https://example.com/path";
        data.setUrl(url);
        assertEquals(url, data.getUrl());

        String url2 = "http://test.org/";
        data.setUrl(url2);
        assertEquals(url2, data.getUrl());

        data.setUrl(null);
        assertNull(data.getUrl());
    }

                && isValidCanonicalUrl(responseData.getUrl(), canonicalUrl)) {
            final Set<RequestData> childUrlSet = new HashSet<>();
            childUrlSet.add(RequestDataBuilder.newRequestData().get().url(canonicalUrl).build());
            logger.info("Canonical URL redirect: from={}, to={}", responseData.getUrl(), canonicalUrl);

                assertTrue(urlQueue.getUrl() + "=>" + url1, urlQueue.getUrl().startsWith(url1));
            }
            while ((urlQueue = urlQueueService.poll(sessionId2)) != null) {
                assertTrue(urlQueue.getUrl() + "=>" + url2, urlQueue.getUrl().startsWith(url2));
            }

            dataService.iterate(sessionId1, accessResult -> assertTrue(accessResult.getUrl().startsWith(url1)));

            if (arMap.containsKey(accessResult.getUrl())) {
                throw new CrawlerSystemException(
                        "AccessResult for URL '" + accessResult.getUrl() + "' already exists. Duplicate URLs are not allowed.");
            }
            arMap.put(accessResult.getUrl(), accessResult);
        }

    }

    /**

        } else if (e.isInfoEnabled()) {
            logger.info(e.getMessage());
        } else if (e.isWarnEnabled()) {
            logger.warn("Crawling access exception at url: {}", urlQueue.getUrl(), e);
        } else if (e.isErrorEnabled()) {
            logger.error("Crawling access exception at url: {}", urlQueue.getUrl(), e);
        }
    }

    /**