assertFailsWith<IOException> {
      requestBody.writeUtf8("request body\n")
      requestBody.flush()
    }.also { expected ->
      assertThat(expected.message)
        .isEqualTo("stream was reset: CANCEL")
    }
    body.awaitSuccess()
    assertThat(listener.recordedEventTypes()).containsExactly(
      "CallStart", "ProxySelectStart", "ProxySelectEnd", "DnsStart", "DnsEnd", "ConnectStart",

          """
          |data: hey
          |
          |
          """.trimMargin(),
        ).setHeader("content-type", "text/event-stream")
        .build(),
    )
    listener.enqueueCancel() // Will cancel in onOpen().
    newEventSource()
    listener.assertOpen()
    listener.assertFailure("canceled")
  }

  @Test
  fun badContentType() {
    server.enqueue(
      MockResponse.Builder()

  private val controlFrameBuffer = Buffer()
  private val messageFrameBuffer = Buffer()

  /** Lazily initialized on first use. */
  private var messageInflater: MessageInflater? = null

  // Masks are only a concern for server writers.
  private val maskKey: ByteArray? = if (isClient) null else ByteArray(4)
  private val maskCursor: Buffer.UnsafeCursor? = if (isClient) null else Buffer.UnsafeCursor()

  interface FrameCallback {

      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) {
  }

  /**

public final class okhttp3/CacheControl$Companion {
	public final fun parse (Lokhttp3/Headers;)Lokhttp3/CacheControl;
}

public abstract interface class okhttp3/Call : java/lang/Cloneable {
	public abstract fun cancel ()V
	public abstract fun clone ()Lokhttp3/Call;
	public abstract fun enqueue (Lokhttp3/Callback;)V
	public abstract fun execute ()Lokhttp3/Response;
	public abstract fun isCanceled ()Z
	public abstract fun isExecuted ()Z

    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