}

  /**
   * Returns true if there's another set of routes to attempt. Every address has at least one route.
   */
  operator fun hasNext(): Boolean = hasNextProxy() || postponedRoutes.isNotEmpty()

  @Throws(IOException::class)
  operator fun next(): Selection {
    if (!hasNext()) throw NoSuchElementException()

    // Compute the next set of routes to attempt.
    val routes = mutableListOf<Route>()

      }
    }
    val outputStream = socket.getOutputStream()
    val inputStream = socket.getInputStream()
    val reader = Http2Reader(inputStream.source().buffer(), client)
    val outFramesIterator: Iterator<OutFrame> = outFrames.iterator()
    val outBytes = bytesOut.readByteArray()
    var nextOutFrame: OutFrame? = null
    for (i in 0 until frameCount) {
      if (nextOutFrame == null && outFramesIterator.hasNext()) {

   */
  private fun promoteAndExecute(): Boolean {
    lock.assertNotHeld()

    val executableCalls = mutableListOf<AsyncCall>()
    val isRunning: Boolean
    this.withLock {
      val i = readyAsyncCalls.iterator()
      while (i.hasNext()) {
        val asyncCall = i.next()

        if (runningAsyncCalls.size >= this.maxRequests) break // Max capacity.