// At 0ms the server sends 3 unexpected pongs. The client accepts 'em and ignores em.
    server.webSocket!!.pong("pong 1".encodeUtf8())
    client.processNextFrame()
    server.webSocket!!.pong("pong 2".encodeUtf8())
    client.processNextFrame()
    taskFaker.runTasks()
    server.webSocket!!.pong("pong 3".encodeUtf8())
    client.processNextFrame()

  private val pingIntervalMillis: Long,
  /**
   * For clients this is initially null, and will be assigned to the agreed-upon extensions. For
   * servers it should be the agreed-upon extensions immediately.
   */
  private var extensions: WebSocketExtensions?,
  /** If compression is negotiated, outbound messages of this size and larger will be compressed. */
  private var minimumDeflateSize: Long,
  private val webSocketCloseTimeout: Long,

   * To differentiate the two cases we ping the server when a stream times out. If the overall
   * connection is fine the ping will receive a pong; otherwise it won't.
   *
   * The deadline to respond to this ping attempts to limit the cost of being wrong. If it is too
   * long, streams created while we await the pong will reuse broken connections and inevitably
   * fail. If it is too short, slow connections will be marked as failed and extra TCP and TLS

      if (queue.futureTasks.isEmpty()) {
        readyQueues.removeAt(i)
      }
    }
  }

  interface Backend {
    fun nanoTime(): Long

    fun coordinatorNotify(taskRunner: TaskRunner)

    fun coordinatorWait(
      taskRunner: TaskRunner,
      nanos: Long,
    )

    fun <T> decorate(queue: BlockingQueue<T>): BlockingQueue<T>

    fun execute(
      taskRunner: TaskRunner,

                  startNextTask()
                }
              }
            }
        }

        override fun coordinatorWait(
          taskRunner: TaskRunner,
          nanos: Long,
        ) {
          taskRunner.assertThreadHoldsLock()
          check(waitingCoordinatorTask == null)
          if (nanos == 0L) return

          // Yield until notified, interrupted, or the duration elapses.

      object : Source {
        private var cacheRequestClosed = false

        @Throws(IOException::class)
        override fun read(
          sink: Buffer,
          byteCount: Long,
        ): Long {
          val bytesRead: Long
          try {
            bytesRead = source.read(sink, byteCount)
          } catch (e: IOException) {
            if (!cacheRequestClosed) {
              cacheRequestClosed = true

# Concurrency and async / await

Details about the `async def` syntax for *path operation functions* and some background about asynchronous code, concurrency, and parallelism.

## In a hurry?

<abbr title="too long; didn't read"><strong>TL;DR:</strong></abbr>

If you are using third party libraries that tell you to call them with `await`, like:

```Python
results = await some_library()
```

   * connection if `streamId` is zero.
   */
  @Throws(IOException::class)
  fun windowUpdate(
    streamId: Int,
    windowSizeIncrement: Long,
  ) {
    this.withLock {
      if (closed) throw IOException("closed")
      require(windowSizeIncrement != 0L && windowSizeIncrement <= 0x7fffffffL) {

    clientListener.assertOpen()

    // Send messages until the client's outgoing buffer overflows!
    val message: ByteString = ByteString.of(*ByteArray(1024 * 1024))
    var messageCount: Long = 0
    while (true) {
      val success = webSocket.send(message)
      if (!success) break
      messageCount++
      val queueSize = webSocket.queueSize()

### `scope`

The spec also says that the client can send another form field "`scope`".

The form field name is `scope` (in singular), but it is actually a long string with "scopes" separated by spaces.

Each "scope" is just a string (without spaces).

They are normally used to declare specific security permissions, for example: