* and response body streams; otherwise resources may be leaked.
   *
   * This method is safe to be called concurrently, but provides limited guarantees. If a transport
   * layer connection has been established (such as a HTTP/2 stream) that is terminated. Otherwise
   * if a socket connection is being established, that is terminated.
   */
  override fun cancel() {

    return writer
  }

  /**
   * Shortens the last frame from its original length to `length`. This will cause the peer to
   * close the socket as soon as this frame has been written; otherwise the peer stays open until
   * explicitly closed.
   */
  fun truncateLastFrame(length: Int): Http2Writer {
    val lastFrame = outFrames.removeAt(outFrames.size - 1)
    require(length < bytesOut.size - lastFrame.start)

    return result.readUtf8()
  }

  /**
   * Converts a single label from Punycode to Unicode.
   *
   * @return true if the range of [string] from [pos] to [limit] was valid and decoded successfully.
   *     Otherwise, the decode failed.
   */
  private fun decodeLabel(
    string: String,
    pos: Int,
    limit: Int,
    result: Buffer,
  ): Boolean {

  // These properties are guarded by [lock].

  /**
   * If true, no new exchanges can be created on this connection. It is necessary to set this to
   * true when removing a connection from the pool; otherwise a racing caller might get it from the
   * pool when it shouldn't. Symmetrically, this must always be checked before returning a
   * connection from the pool.
   *
   * Once true this is always true. Guarded by this.
   */

      listener.cacheMiss(call)
    }

    var networkResponse: Response? = null
    try {
      networkResponse = chain.proceed(networkRequest)
    } finally {
      // If we're crashing on I/O or otherwise, don't leak the cache body.
      if (networkResponse == null && cacheCandidate != null) {
        cacheCandidate.body.closeQuietly()
      }
    }

     *
     * @param protocols the protocols to use, in order of preference. If the list contains
     *     [Protocol.H2_PRIOR_KNOWLEDGE] then that must be the only protocol and HTTPS URLs will not
     *     be supported. Otherwise the list must contain [Protocol.HTTP_1_1]. The list must
     *     not contain null or [Protocol.HTTP_1_0].
     */
    fun protocols(protocols: List<Protocol>) =
      apply {

 *     .url("http://publicobject.com/helloworld.txt")
 *     .build();
 * ```
 *
 * ## Force a Cache Response
 *
 * Sometimes you'll want to show resources if they are available immediately, but not otherwise.
 * This can be used so your application can show *something* while waiting for the latest data to be
 * downloaded. To restrict a request to locally-cached resources, add the `only-if-cached`
 * directive:
 *

      }
    }
  }

  /**
   * Returns this if its [connectionSpecIndex] is defined, or a new connection with it defined
   * otherwise.
   */
  @Throws(IOException::class)
  internal fun planWithCurrentOrInitialConnectionSpec(
    connectionSpecs: List<ConnectionSpec>,
    sslSocket: SSLSocket,
  ): ConnectPlan {

   * expect a newly-started thread to call [Runnable.run]. We shouldn't request new threads until
   * the already-requested ones are in service, otherwise we might create more threads than we need.
   *
   * We use [executeCallCount] and [runCallCount] to defend against starting more threads than we
   * need. Both fields are guarded by [lock].
   */

  /**
   * Constructs a new request.
   *
   * Use [Builder] for more fluent construction, including helper methods for various HTTP methods.
   *
   * @param method defaults to "GET" if [body] is null, and "POST" otherwise.
   */
  constructor(
    url: HttpUrl,
    headers: Headers = headersOf(),
    // '\u0000' is a sentinel value that'll choose based on what the body is:
    method: String = "\u0000",
    body: RequestBody? = null,