crawler2.getCrawlerContext().setNumOfThread(numOfThread);

            final String sessionId1 = crawler1.execute();
            final String sessionId2 = crawler2.execute();

            assertNotSame(sessionId1, sessionId2);
            assertNotSame(crawler1.crawlerContext, crawler2.crawlerContext);

            // Wait for both crawlers to start with polling

            crawler2.getCrawlerContext().setNumOfThread(numOfThread);

            final String sessionId1 = crawler1.execute();
            final String sessionId2 = crawler2.execute();

            assertNotSame(sessionId1, sessionId2);
            assertNotSame(crawler1.crawlerContext, crawler2.crawlerContext);

            for (int i = 0; i < 100; i++) {

            crawler2.getCrawlerContext().setNumOfThread(numOfThread);

            final String sessionId1 = crawler1.execute();
            final String sessionId2 = crawler2.execute();

            assertNotSame(sessionId1, sessionId2);
            assertNotSame(crawler1.crawlerContext, crawler2.crawlerContext);

            // Wait for both crawlers to start with polling

    public void test_processUrl_emptyUrl() {
        String sessionId = "test-session-014";
        urlFilter.init(sessionId);

        urlFilter.processUrl("");
        // Should handle empty URL gracefully
        assertNotNull(urlFilter);
    }

    /**
     * Test clear method
     */
    public void test_clear() {
        String sessionId = "test-session-015";
        urlFilter.init(sessionId);

        server.start();

        final String url = "http://localhost:7070/hoge.html";
        try {
            final CrawlerContext crawlerContext = new CrawlerContext();
            final String sessionId = "id1";
            urlFilter.init(sessionId);
            crawlerContext.setUrlFilter(urlFilter);
            CrawlingParameterUtil.setCrawlerContext(crawlerContext);
            httpClient.init();
            httpClient.processRobotsTxt(url);

    }

    /**
     * Test implementation of UrlFilter for testing
     */
    private static class TestUrlFilter implements UrlFilter {
        @Override
        public void init(String sessionId) {
        }

        @Override
        public void addInclude(String urlPattern) {
        }

        @Override
        public void addExclude(String urlPattern) {
        }

        @Override

```python
from typing import Annotated

from fastapi import Cookie, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Cookies(BaseModel):
    session_id: str
    fatebook_tracker: str | None = None
    googall_tracker: str | None = None


@app.get("/items/")
async def read_items(cookies: Annotated[Cookies, Cookie()]):
    return cookies
```