@Throws(IOException::class)
  override fun proceed(request: Request): Response {
    check(index < interceptors.size)

    calls++

    if (exchange != null) {
      check(exchange.finder.routePlanner.sameHostAndPort(request.url)) {
        "network interceptor ${interceptors[index - 1]} must retain the same host and port"
      }
      check(calls == 1) {

    return result
  }

  override fun hasNext(failedConnection: RealConnection?): Boolean =
    deferredPlans.isNotEmpty() || nextPlanIndex < plans.size || autoGeneratePlans

  override fun sameHostAndPort(url: HttpUrl): Boolean = url.host == address.url.host && url.port == address.url.port

  override fun close() {
    factory.close()
  }

  inner class FakePlan(
    val id: Int,
  ) : RoutePlanner.Plan {

   * detect if followups need to do a full connection-finding process including DNS resolution, and
   * certificate pin checks.
   */
  fun sameHostAndPort(url: HttpUrl): Boolean

  /**
   * A plan holds either an immediately-usable connection, or one that must be connected first.
   * These steps are split so callers can call [connectTcp] on a background thread if attempting