private val busyQueues = mutableListOf<TaskQueue>()

  /** Queues not in [busyQueues] that have non-empty [TaskQueue.futureTasks]. */
  private val readyQueues = mutableListOf<TaskQueue>()

  private val runnable: Runnable =
    object : Runnable {
      override fun run() {
        var incrementedRunCallCount = false
        while (true) {
          val task =
            ******@****.***ck {

        " to " + redactedUrl()
    )
  }

  internal fun redactedUrl(): String = originalRequest.url.redact()

  inner class AsyncCall(
    private val responseCallback: Callback,
  ) : Runnable {
    @Volatile var callsPerHost = AtomicInteger(0)
      private set

    fun reuseCallsPerHostFrom(other: AsyncCall) {
      this.callsPerHost = other.callsPerHost
    }

    val host: String

    TaskRunner(
      object : TaskRunner.Backend {
        override fun execute(
          taskRunner: TaskRunner,
          runnable: Runnable,
        ) {
          taskRunner.assertThreadHoldsLock()

          val queuedTask = RunnableSerialTask(runnable)
          serialTaskQueue += queuedTask
          executeCallCount++
          isParallel = serialTaskQueue.size > 1
        }

  private val dispatcherTest: DispatcherTest,
) : AbstractExecutorService() {
  private var shutdown: Boolean = false
  private val calls = mutableListOf<RealCall.AsyncCall>()

  override fun execute(command: Runnable) {
    if (shutdown) throw RejectedExecutionException()
    calls.add(command as RealCall.AsyncCall)
  }

  fun assertJobs(vararg expectedUrls: String) {
    val actualUrls = calls.map { it.request.url.toString() }

  private val loggingUncaughtExceptionHandler =
    UncaughtExceptionHandler { _, throwable ->
      log.put("uncaught exception: $throwable")
    }

  private val threadFactory =
    ThreadFactory { runnable ->
      Thread(runnable, "TaskRunnerRealBackendTest").apply {
        isDaemon = true
        uncaughtExceptionHandler = loggingUncaughtExceptionHandler
      }
    }

  private val backend = TaskRunner.RealBackend(threadFactory)

@JvmField
internal val UTC: TimeZone = TimeZone.getTimeZone("GMT")!!

internal fun threadFactory(
  name: String,
  daemon: Boolean,
): ThreadFactory =
  ThreadFactory { runnable ->
    Thread(runnable, name).apply {
      isDaemon = daemon
    }
  }

internal fun HttpUrl.toHostHeader(includeDefaultPort: Boolean = false): String {
  val host =
    if (":" in host) {
      "[$host]"
    } else {

  }

  @JvmStatic
  fun threadFactory(name: String): ThreadFactory {
    return object : ThreadFactory {
      private var nextId = 1

      override fun newThread(runnable: Runnable): Thread {
        return Thread(runnable, "$name-${nextId++}")
      }
    }
  }
}

fun getEnv(name: String) = System.getenv(name)

val SYSTEM_FILE_SYSTEM = FileSystem.SYSTEM

    ThreadPoolExecutor(1, 1, 0, TimeUnit.SECONDS, SynchronousQueue()) {
    private val exceptions: BlockingQueue<Exception> = LinkedBlockingQueue()

    override fun execute(runnable: Runnable) {
      super.execute {
        try {
          runnable.run()
        } catch (e: Exception) {
          exceptions.add(e)
        }
      }
    }

    fun takeException(): Exception {
      return exceptions.take()

   * This means that if you are doing synchronous calls the network layer will not truly be idle
   * until every returned [Response] has been closed.
   */
  var idleCallback: Runnable? = null
    get() = this.withLock { field }
    set(value) {
      this.withLock { field = value }
    }

  private var executorServiceOrNull: ExecutorService? = null

  @get:JvmName("executorService")

  private val factory = routePlanner.factory
  private val taskFaker = routePlanner.taskFaker
  private val peer = MockHttp2Peer()

  /** The fake task runner prevents the cleanup runnable from being started.  */
  private val addressA = factory.newAddress("a")
  private val routeA1 = factory.newRoute(addressA)
  private val addressB = factory.newAddress("b")
  private val routeB1 = factory.newRoute(addressB)