line application hang after all of the work is done, it may be due to a non-daemon thread like
    this one.
 *  New: Include suppressed exceptions when all routes to a target service fail.


## Version 4.4.1

_2020-03-08_

 *  Fix: Don't reuse a connection on redirect if certs match but DNS does not. For better

   * (unless they were already returned).
   *
   * The iterator supports [MutableIterator.remove]. Removing a URL from the iterator evicts the
   * corresponding response from the cache. Use this to evict selected responses.
   */
  @Throws(IOException::class)
  fun urls(): MutableIterator<String> {
    return object : MutableIterator<String> {

   * When we need a new thread to run tasks, we call [Backend.execute]. A few microseconds later we
   * 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].
   */

      throw AssertionError("Thread ${Thread.currentThread().name} MUST NOT hold lock on $this")
    }
  }

  val logger = Logger.getLogger("TaskFaker." + instance++)

  /** Though this executor service may hold many threads, they are not executed concurrently. */
  private val tasksExecutor = Executors.newCachedThreadPool(threadFactory("TaskFaker"))

  /**

    override fun alternateService(
      streamId: Int,
      origin: String,
      protocol: ByteString,
      host: String,
      port: Int,
      maxAge: Long,
    ) {
      // TODO: register alternate service.
    }
  }

  /** Even, positive numbered streams are pushed streams in HTTP/2. */
  internal fun pushedStream(streamId: Int): Boolean = streamId != 0 && streamId and 1 == 0

  internal fun pushRequestLater(

      }

      else -> {
        toEvict = null
        toEvictIdleAtNs = -1L
      }
    }

    when {
      toEvict != null -> {
        // We've chosen a connection to evict. Confirm it's still okay to be evicted, then close it.
        toEvict.withLock {
          if (toEvict.calls.isNotEmpty()) return 0L // No longer idle.