* [system DNS service][SYSTEM], which is the default. Some applications may provide their own
 * implementation to use a different DNS server, to prefer IPv6 addresses, to prefer IPv4 addresses,
 * or to force a specific known IP address.
 *
 * Implementations of this interface must be safe for concurrent use.
 */
fun interface Dns {
  /**

    // Write metadata to the end of the file.
    writeMetadata(upstreamSize)
    file!!.channel.force(false)

    // Once everything else is in place we can swap the dirty header for a clean one.
    writeHeader(PREFIX_CLEAN, upstreamSize, metadata.size.toLong())
    file!!.channel.force(false)

    // This file is complete.
    synchronized(this@Relay) {
      complete = true
    }

        val headers = request.headers

        if (requestBody != null) {
          // Request body headers are only present when installed as a network interceptor. When not
          // already present, force them to be included (if available) so their values are known.
          requestBody.contentType()?.let {
            if (headers["Content-Type"] == null) {
              logger.log("Content-Type: $it")
            }

      "FGHIJKLMNOPQRSTUVWXYZ",
    )
    inputStream.close()
    assertContent("ABCDEFGHIJKLMNOPQRSTUVWXYZ", getResponse(newRequest("/")))
  }

  /**
   * We've had a bug where we forget the HTTP response when we see response code 401. This causes a
   * new HTTP request to be issued for every call into the URLConnection.
   */
  @Test
  fun unauthorizedResponseHandling() {
    val mockResponse =

    val noTransform: Boolean = cacheControl.noTransform
    val immutable: Boolean = cacheControl.immutable
    val forceCache: CacheControl = CacheControl.FORCE_CACHE
    val forceNetwork: CacheControl = CacheControl.FORCE_NETWORK
    val parse: CacheControl = CacheControl.parse(headersOf())
  }

  @Test
  fun cacheControlBuilder() {
    var builder: CacheControl.Builder = CacheControl.Builder()

      listener.onClosed(this, code, reason!!)
    }

    readerToClose?.closeQuietly()
    streamsToClose?.closeQuietly()
  }

  /** For testing: force this web socket to release its threads. */
  @Throws(InterruptedException::class)
  fun tearDown() {
    taskQueue.shutdown()
    taskQueue.idleLatch().await(10, TimeUnit.SECONDS)
  }

  }

  @Test
  fun satisfactionFailure() {
    enableCache()
    val call =
      client.newCall(
        Request.Builder()
          .url(server.url("/"))
          .cacheControl(CacheControl.FORCE_CACHE)
          .build(),
      )
    val response = call.execute()
    assertThat(response.code).isEqualTo(504)
    response.close()
    assertThat(listener.recordedEventTypes())

    set("a", "a1234", "a1234")
    val a = cache.edit("a")!!
    a.setString(0, "a123")
    cache.maxSize = 8 // Smaller than the sum of active edits!
    cache.flush() // Force trimToSize().
    assertThat(cache.size()).isEqualTo(expectedByteCount)
    assertThat(readFileOrNull(getCleanFile("a", 0))).isEqualTo(afterRemoveFileContents)

      if (i == 2) {
        // Force this request's response to be written to the cache. This way, subsequent responses
        // can be read from the cache.
        System.out.println("Force cache: true");
        clientForCall = client.newBuilder()
            .addNetworkInterceptor(REWRITE_CACHE_CONTROL_INTERCEPTOR)
            .build();
      } else {
        System.out.println("Force cache: false");
        clientForCall = client;

      }
    assertThat(requestsMade.size).isEqualTo(0)
    mockWebServer.dispatcher = dispatcher
    val url = mockWebServer.url("/").toUrl()
    val conn = url.openConnection() as HttpURLConnection
    conn.responseCode // Force the connection to hit the "server".
    // Make sure our dispatcher got the request.
    assertThat(requestsMade.size).isEqualTo(1)
  }

  @Test
  fun outOfOrderResponses() {
    val firstResponseCode = AtomicInteger()