encodings[ 0x15] = encoding // Negative Acknowledgment
      encodings[ 0x16] = encoding // Synchronous idle
      encodings[ 0x17] = encoding // End of Transmission Block
      encodings[ 0x18] = encoding // Cancel
      encodings[ 0x19] = encoding // End of Medium
      encodings[ 0x1a] = encoding // Substitute
      encodings[ 0x1b] = encoding // Escape
      encodings[ 0x1c] = encoding // File Separator

    val connectionClose = CountDownLatch(1)
    val streams =
      object : RealWebSocket.Streams(false, source, sink) {
        override fun close() = connectionClose.countDown()

        override fun cancel() {
          socket.closeQuietly()
        }
      }
    val webSocket =
      RealWebSocket(
        taskRunner = taskRunner,
        originalRequest = fancyRequest,

   * occur after a call is canceled. Typically cancellation takes effect when an expensive I/O
   * operation is required.
   *
   * This is invoked at most once, even if [Call.cancel] is invoked multiple times. It may be
   * invoked at any point in a call's life, including before [callStart] and after [callEnd].
   */
  open fun canceled(call: Call) {
  }

  /**

      object : Call {
        override fun request(): Request = TODO()

        override fun execute(): Response = TODO()

        override fun enqueue(responseCallback: Callback) = TODO()

        override fun cancel() = TODO()

        override fun isExecuted(): Boolean = TODO()

        override fun isCanceled(): Boolean = TODO()

        override fun timeout(): Timeout = TODO()

    assertEvents(
      "take plan 1",
      "plan 1 TCP connecting...",
    )

    taskFaker.advanceUntil(500.ms)
    assertEvents(
      "take plan 2",
      "plan 0 cancel",
      "plan 1 cancel",
    )

    taskFaker.advanceUntil(510.ms)
    assertEvents(
      "plan 1 TCP connect canceled",
    )

    taskFaker.advanceUntil(520.ms)
    assertEvents(

  }

  private fun cancelLater(
    call: Call,
    delayMillis: Int,
  ): CountDownLatch {
    val latch = CountDownLatch(1)
    Thread {
      sleep(delayMillis)
      if (cancelMode == CANCEL) {
        call.cancel()
      } else {
        threadToCancel!!.interrupt()
      }
      latch.countDown()
    }.apply { start() }
    return latch
  }

  companion object {

that by default Kotlin's Dispatchers are not used.

Cancellation if implemented sensibly in both directions.
Cancelling a coroutine scope, will cancel the call.
Cancelling a call, will throw a CancellationException

  /** Returns the trailers after the HTTP response. May be empty. */
  @Throws(IOException::class)
  fun trailers(): Headers

  /**
   * Cancel this stream. Resources held by this stream will be cleaned up, though not synchronously.
   * That may happen later by the connection pool thread.
   */
  fun cancel()

  /**
   * Carries an exchange. This is usually a connection, but it could also be a connect plan for

    stream = http2Connection.newStream(requestHeaders, hasRequestBody)
    // We may have been asked to cancel while creating the new stream and sending the request
    // headers, but there was still no stream to close.
    if (canceled) {
      stream!!.closeLater(ErrorCode.CANCEL)
      throw IOException("Canceled")
    }
    stream!!.readTimeout().timeout(chain.readTimeoutMillis.toLong(), TimeUnit.MILLISECONDS)

  override fun connectTcp() = error("already connected")

  override fun connectTlsEtc() = error("already connected")

  override fun handleSuccess() = connection

  override fun cancel() = error("unexpected cancel")

  override fun retry() = error("unexpected retry")