`requestBodyEnd()`, both on the same call. Such events may be triggered by different threads
    even for a single call.

    Interceptors that rewrite or replace the request body may now inadvertently interfere with
    duplex request bodies. Such interceptors should check `RequestBody.isDuplex()` and avoid
    accessing the request body when it is.

    return nextTask
  }

  private interface SerialTask {
    /** Returns true if this task is ready to start. */
    fun isReady() = true

    /** Do this task's work, and then start another, such as by calling [startNextTask]. */
    fun start()
  }

  private object TestThreadSerialTask : SerialTask {
    override fun start() = error("unexpected call")
  }

  inner class RunnableSerialTask(

    }

    fun build(): CacheControl = commonBuild()
  }

  companion object {
    /**
     * Cache control request directives that require network validation of responses. Note that such
     * requests may be assisted by the cache via conditional GET requests.
     */
    @JvmField
    val FORCE_NETWORK = commonForceNetwork()

    /**

 *   }
 *
 *   public void onFailure(Call call, IOException e) {
 *   ... // Handle the failure.
 *   }
 * });
 * ```
 *
 * These examples will not work if you're consuming the response body on another thread. In such
 * cases the consuming thread must call [close] when it has finished reading the response
 * body.
 *
 * ### The response body can be consumed only once.
 *

 * `http://ho™ail.com`. To mitigate this, the single character (™) maps to the string (tm). There
 * is similar policy for all of the 1.1 million Unicode code points. Note that some code points such
 * as "\ud83c\udf69" are not mapped and cannot be used in a hostname.
 *
 * [Punycode](http://ietf.org/rfc/rfc3492.txt) converts a Unicode string to an ASCII string to make

    assertThat(body.contentLength()).isEqualTo(3)
    assertThat(bodyToHex(body)).isEqualTo("616263")
    assertThat(bodyToHex(body), "Retransmit body").isEqualTo("616263")
  }

  /** Common verbs used for apis such as GitHub, AWS, and Google Cloud.  */
  @Test
  fun crudVerbs() {
    val contentType = "application/json".toMediaType()
    val body = "{}".toRequestBody(contentType)

     *     represented as a combination of scheme, host and port. When empty, the origin is that of
     *     the `streamId`.
     * @param protocol an ALPN protocol, such as `h2`.
     * @param host an IP address or hostname.
     * @param port the IP port associated with the service.
     * @param maxAge time in seconds that this alternative is considered fresh.
     */

  fun reset() {
    hpackReader = newReader(bytesIn)
    hpackWriter = Hpack.Writer(4096, false, bytesOut)
  }

  /**
   * Variable-length quantity special cases strings which are longer than 127 bytes.  Values such as
   * cookies can be 4KiB, and should be possible to send.
   *
   *  http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-12#section-5.2
   */
  @Test
  fun largeHeaderValue() {

     * Returns an error for the DNS query.
     */
    fun onFailure(
      hostname: String,
      e: IOException,
    )
  }

  /**
   * Class of DNS addresses, such that clients that treat these differently, such
   * as attempting IPv6 first, can make such decisions.
   */
  @ExperimentalOkHttpApi
  enum class DnsClass(val type: Int) {
    IPV4(TYPE_A),
    IPV6(TYPE_AAAA),
  }

  @ExperimentalOkHttpApi

 *     [RealConnection.isEligible] for details.
 *
 *  3. Attempt plans from prior connect attempts for this call. These occur as either follow-ups to
 *     failed connect attempts (such as trying the next [ConnectionSpec]), or as attempts that lost
 *     a race in fast follow-up.
 *
 *  4. If there's no existing connection, make a list of routes (which may require blocking DNS