val value = source.readInt()

      when (id) {
        // SETTINGS_HEADER_TABLE_SIZE
        1 -> {
        }

        // SETTINGS_ENABLE_PUSH
        2 -> {
          if (value != 0 && value != 1) {
            throw IOException("PROTOCOL_ERROR SETTINGS_ENABLE_PUSH != 0 or 1")
          }
        }

        // SETTINGS_MAX_CONCURRENT_STREAMS

      else -> println(message)
    }
  }

  fun enableJsseDebugLogging(debugHandler: (JsseDebugMessage) -> Unit = this::quietDebug): Closeable {
    System.setProperty("javax.net.debug", "")
    return OkHttpDebugLogging.enable(
      "javax.net.ssl",
      object : Handler() {
        override fun publish(record: LogRecord) {
          val param = record.parameters?.firstOrNull() as? String

    mutual TLS where these roles are reversed.

    These classes make it possible to enable HTTPS in MockWebServer in [just a few lines of
    code][https_server_sample].

 *  **OkHttp now supports prior knowledge cleartext HTTP/2.** Enable this by setting
    `Protocol.H2_PRIOR_KNOWLEDGE` as the lone protocol on an `OkHttpClient.Builder`. This mode

        .allEnabledTlsVersions()
        .allEnabledCipherSuites()
        .build()
    assertThat(connectionSpec.toString()).isEqualTo(
      "ConnectionSpec(cipherSuites=[all enabled], tlsVersions=[all enabled], " +
        "supportsTlsExtensions=true)",
    )
  }

  @Test
  fun simpleToString() {
    val connectionSpec =
      ConnectionSpec.Builder(ConnectionSpec.MODERN_TLS)

       the generated index.xml, are outputs, not inputs. We can be sure of
       this because they are deleted in the @BeforeEach method of the
       OsgiTest test class.

       - To enable the benefit of incremental builds, we can ask Gradle
       to ignore these two files when considering whether the classpath
       has changed. That is the purpose of this normalization block.
   */

If you're in a tricky situation and prepared to deal with the consequences, rewriting response headers is a powerful way to work around problems. For example, you can fix a server's misconfigured `Cache-Control` response header to enable better response caching:

```java
/** Dangerous interceptor that rewrites the server's cache-control header. */
private static final Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = new Interceptor() {

          .apply {
            isAccessible = true
          }
          .get(this) as? SecretKey

    val randomRegex = "\"random\"\\s+:\\s+\"([^\"]+)\"".toRegex()

    fun register() {
      // Enable JUL logging for SSL events, must be activated early or via -D option.
      System.setProperty("javax.net.debug", "")
      logger =
        Logger.getLogger("javax.net.ssl")
          .apply {

    )
    assertThat(webSocket.close(1000, null)).isFalse()
  }

  /**
   * There's no read timeout when reading the first byte of a new frame. But as soon as we start
   * reading a frame we enable the read timeout. In this test we have the server returning the first
   * byte of a frame but no more frames.
   */
  @Test
  fun readTimeoutAppliesWithinFrames() {
    webServer.dispatcher =

    server.shutdown()
    executeSynchronously("/")
      .assertFailure(IOException::class.java)
  }

  @Test
  fun requestBodySurvivesRetries() {
    server.enqueue(MockResponse())

    // Enable a misconfigured proxy selector to guarantee that the request is retried.
    client =
      client.newBuilder()
        .proxySelector(
          FakeProxySelector()
            .addProxy(server2.toProxyAddress())

**not stable** and will likely change before the final 5.0.0 release.

If you have code that subclasses `okhttp3.mockwebserver.QueueDispatcher`, this update is not source
or binary compatible. Migrating to the new `mockwebserver3` package will fix this problem.

 *  New: DNS over HTTPS is now a stable feature of OkHttp. We introduced this as an experimental