open fun trailers(trailersSource: TrailersSource): Builder =
      apply {
        this.trailersSource = trailersSource
      }

    open fun sentRequestAtMillis(sentRequestAtMillis: Long) =
      apply {
        this.sentRequestAtMillis = sentRequestAtMillis
      }

    open fun receivedResponseAtMillis(receivedResponseAtMillis: Long) =
      apply {
        this.receivedResponseAtMillis = receivedResponseAtMillis

        val response =
          cacheResponse
            .newBuilder()
            .headers(combine(cacheResponse.headers, networkResponse.headers))
            .sentRequestAtMillis(networkResponse.sentRequestAtMillis)
            .receivedResponseAtMillis(networkResponse.receivedResponseAtMillis)
            .cacheResponse(cacheResponse.stripBody())
            .networkResponse(networkResponse.stripBody())

        .Builder()
        .request(proxyConnectRequest)
        .protocol(Protocol.HTTP_1_1)
        .code(HttpURLConnection.HTTP_PROXY_AUTH)
        .message("Preemptive Authenticate")
        .sentRequestAtMillis(-1L)
        .receivedResponseAtMillis(-1L)
        .header("Proxy-Authenticate", "OkHttp-Preemptive")
        .build()

    val authenticatedRequest =
      route.address.proxyAuthenticator

    val cacheResponse: Response? = response.cacheResponse()
    val priorResponse: Response? = response.priorResponse()
    val cacheControl: CacheControl = response.cacheControl()
    val sentRequestAtMillis: Long = response.sentRequestAtMillis()
    val receivedResponseAtMillis: Long = response.receivedResponseAtMillis()
  }

  @Test @Disabled
  fun route() {
    val route: Route = factory.newRoute()

 * **Request**: body, cacheControl, headers, method, url
 * **Response**: body, cacheControl, cacheResponse, code, handshake, headers, message,
   networkResponse, priorResponse, protocol, receivedResponseAtMillis, request, sentRequestAtMillis
 * **Route**: address, proxy, socketAddress
 * **TlsVersion**: javaName

#### Renamed Functions

* **Headers.of()**: for symmetry with `listOf()`, `setOf()`, etc., we’ve replaced

    private fun isFreshnessLifetimeHeuristic(): Boolean = cacheResponse!!.cacheControl.maxAgeSeconds == -1 && expires == null

    init {
      if (cacheResponse != null) {
        this.sentRequestMillis = cacheResponse.sentRequestAtMillis
        this.receivedResponseMillis = cacheResponse.receivedResponseAtMillis
        val headers = cacheResponse.headers
        for (i in 0 until headers.size) {
          val fieldName = headers.name(i)