override fun contentType(): MediaType? = null

    override fun writeTo(sink: BufferedSink) {
      for (i in 0 until 50) {
        sink.writeUtf8("abc")
        sink.flush()
        Thread.sleep(100)
      }
      fail("")
    }
  }

    MockReference(FinalizableReferenceQueue frq) {
      super(new Object(), frq);
    }

    @Override
    public void finalizeReferent() {
      finalizeReferentCalled = true;
    }
  }

  /**
   * Keeps a weak reference to the underlying reference queue. When this reference is cleared, we
   * know that the background thread has stopped and released its strong reference.
   */

    MockReference(FinalizableReferenceQueue frq) {
      super(new Object(), frq);
    }

    @Override
    public void finalizeReferent() {
      finalizeReferentCalled = true;
    }
  }

  /**
   * Keeps a weak reference to the underlying reference queue. When this reference is cleared, we
   * know that the background thread has stopped and released its strong reference.
   */

With fast fallback, OkHttp attempts to connect to multiple web servers concurrently. It keeps whichever route connects first and cancels all of the others. Its rules are:

 * Prefer to alternate IP addresses from different address families, (IPv6 / IPv4), starting with IPv6.

        // Make the cache entry expired
        DirectoryCacheEntry entry = directoryLeaseManager.getCacheEntry(directoryPath);
        entry.setMaxAge(1); // 1ms to expire immediately
        try {
            Thread.sleep(10);
        } catch (InterruptedException e) {
            // Ignore
        }

        // When lease is lost, cache entry should be removed
        when(baseLeaseManager.getLease(leaseKey)).thenReturn(null);

Using a relative URL is important to make sure your application keeps working even in an advanced use case like [Behind a Proxy](../../advanced/behind-a-proxy.md){.internal-link target=_blank}.

///

        entry.setMaxAge(100); // 100ms

        assertFalse(entry.isExpired());
        assertFalse(entry.needsRefresh());

        // Wait for expiration
        try {
            Thread.sleep(150);
        } catch (InterruptedException e) {
            // Ignore
        }

        assertTrue(entry.isExpired());
        assertTrue(entry.needsRefresh());
    }

    @Test

    }
  }

  @Test
  fun fullCallTimeoutDoesNotApplyOnceConnected() {
    enableProtocol(Protocol.HTTP_2)
    val body =
      MockSocketHandler()
        .sendResponse("response A\n")
        .sleep(750, TimeUnit.MILLISECONDS)
        .sendResponse("response B\n")
        .receiveRequest("request C\n")
        .exhaustResponse()
        .exhaustRequest()
    server.enqueue(
      MockResponse

        createJob();
        logger.info("Job is created: {}", webConfigId);
        refresh();

        startJob(NAME_PREFIX);

        waitJob(NAME_PREFIX);
        refresh();

        ThreadUtil.sleep(3000);
    }

    @BeforeEach
    protected void init() {
        refresh();
    }

    @AfterEach
    protected void tearDown() {
    }

    @AfterAll
    protected static void tearDownAll() {

for HTTPS:

```java
HeldCertificate localhostCertificate = new HeldCertificate.Builder()
    .addSubjectAlternativeName("localhost")
    .build();
```

[`HandshakeCertificates`][handshake_certificates] keeps the certificates for a TLS handshake.
Use its [builder][handshake_certificates_builder] to define which certificates the HTTPS server
returns to its clients. The returned instance can create an `SSLSocketFactory` that implements this