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{* ../../docs_src/custom_request_and_route/tutorial003_py310.py hl[26] *}

Nesse exemplo, as *operações de rota* sob o `router` irão usar a classe `TimedRoute` personalizada, e terão um cabeçalho extra `X-Response-Time` na resposta com o tempo que levou para gerar a resposta:

        String output = testOutput.toString();
        assertTrue(output.contains("test message"));
    }

    @Test
    void testSetInstanceMultipleTimes() {
        // Test setting instance multiple times
        PrintStream stream1 = new PrintStream(new ByteArrayOutputStream());
        PrintStream stream2 = new PrintStream(new ByteArrayOutputStream());

        LogStream.setInstance(stream1);

query_or_cookie_extractor(["query_or_cookie_extractor"])

read_query["/items/"]

query_extractor --> query_or_cookie_extractor --> read_query
```

## 같은 의존성을 여러 번 사용하기 { #using-the-same-dependency-multiple-times }

같은 *경로 처리*에 대해 의존성 중 하나가 여러 번 선언되는 경우(예: 여러 의존성이 공통 하위 의존성을 갖는 경우), **FastAPI**는 그 하위 의존성을 요청당 한 번만 호출해야 한다는 것을 알고 있습니다.

query_or_cookie_extractor(["query_or_cookie_extractor"])

read_query["/items/"]

query_extractor --> query_or_cookie_extractor --> read_query
```

## 多次使用同一個相依項 { #using-the-same-dependency-multiple-times }

如果你的某個相依項在同一個路徑操作中被宣告了多次，例如多個相依共用同一個子相依，**FastAPI** 會知道只需在每次請求中呼叫該子相依一次。

它會把回傳值儲存在一個 <dfn title="用來儲存已計算/產生之值的工具／系統，以便重複使用而不必再次計算。">「快取」</dfn> 中，並在該次請求中傳遞給所有需要它的「相依者」，而不是為同一個請求多次呼叫相同的相依項。

				Computed: etag,
			}
		}
	}
	return n, err
}

// ETag returns the ETag of all the content read
// so far. Reading more content changes the MD5
// checksum. Therefore, calling ETag multiple
// times may return different results.
func (r *Reader) ETag() ETag {
	sum := r.md5.Sum(nil)
	return ETag(sum)
}

// VerifyError is an error signaling that a
// computed ETag does not match an expected
// ETag.

import java.util.concurrent.atomic.AtomicInteger;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests relating to cache expiration: make sure entries expire at the right times, make sure
 * expired entries don't show up, etc.
 *
 * @author mike nonemacher
 */
@SuppressWarnings("deprecation") // tests of deprecated method
@NullUnmarked
public class CacheExpirationTest extends TestCase {

        };
        ComponentUtil.setFessConfig(mockConfig);

        // Setup mock request manager
        RequestManager mockRequestManager = createMockRequestManager("de_DE");

        // Execute multiple times
        OptionalThing<Locale> result1 = provider.findBusinessLocale(null, mockRequestManager);
        OptionalThing<Locale> result2 = provider.findBusinessLocale(null, mockRequestManager);

      return bytes;
    }

    @Override
    boolean equalsSameBits(HashCode that) {
      // We don't use MessageDigest.isEqual() here because its contract does not guarantee
      // constant-time evaluation (no short-circuiting).
      if (this.bytes.length != that.getBytesInternal().length) {
        return false;
      }

      boolean areEqual = true;
      for (int i = 0; i < this.bytes.length; i++) {

 * dataset contains no finite values).
 *
 * <h3>Performance</h3>
 *
 * <p>The average time complexity of the computation is O(N) in the size of the dataset. There is a
 * worst case time complexity of O(N^2). You are extremely unlikely to hit this quadratic case on
 * randomly ordered data (the probability decreases faster than exponentially in N), but if you are