* cache-control headers.
     */
    open fun cacheControl(cacheControl: CacheControl): Builder = commonCacheControl(cacheControl)

    open fun get(): Builder = commonGet()

    open fun head(): Builder = commonHead()

    open fun post(body: RequestBody): Builder = commonPost(body)

    @JvmOverloads
    open fun delete(body: RequestBody? = commonEmptyRequestBody): Builder = commonDelete(body)

   * messages.
   */
  open fun onOpen(
    webSocket: WebSocket,
    response: Response,
  ) {
  }

  /** Invoked when a text (type `0x1`) message has been received. */
  open fun onMessage(
    webSocket: WebSocket,
    text: String,
  ) {
  }

  /** Invoked when a binary (type `0x2`) message has been received. */
  open fun onMessage(
    webSocket: WebSocket,

   */
  open fun connectStart(
    route: Route,
    call: Call,
  ) {}

  /**
   * Invoked when a connection fails to be established.
   */
  open fun connectFailed(
    route: Route,
    call: Call,
    failure: IOException,
  ) {}

  /**
   * Invoked as soon as a connection is successfully established.
   */
  open fun connectEnd(
    connection: Connection,

  fun enqueueCancel() {
    cancel = true
  }

  override fun onOpen(
    eventSource: EventSource,
    response: Response,
  ) {
    get().log("[ES] onOpen", Platform.INFO, null)
    events.add(Open(eventSource, response))
    drainCancelQueue(eventSource)
  }

  override fun onEvent(
    eventSource: EventSource,
    id: String?,
    type: String?,
    data: String,
  ) {

 *
 * ### Android Cleartext Permit Detection
 *
 * Supported on Android 6.0+ via `NetworkSecurityPolicy`.
 */
open class Platform {
  /** Prefix used on custom headers. */
  fun getPrefix() = "OkHttp"

  open fun newSSLContext(): SSLContext = SSLContext.getInstance("TLS")

  open fun platformTrustManager(): X509TrustManager {
    val factory =
      TrustManagerFactory.getInstance(

    } else {
      eventSequence.forEach loop@{
        when (e.closes(it)) {
          null -> return // no open event
          true -> return // found open event
          false -> return@loop // this is not the open event so continue
        }
      }
      fail<Any>("event $e without matching start event")
    }
  }

  override fun proxySelectStart(

   */
  open fun callStart(call: Call) {
  }

  /**
   * Invoked prior to a proxy selection.
   *
   * This will be invoked for route selection regardless of whether the client
   * is configured with a single proxy, a proxy selector, or neither.
   *
   * @param url a URL with only the scheme, hostname, and port specified.
   */
  open fun proxySelectStart(
    call: Call,

      this.trailersFn = response.trailersFn
    }

    open fun request(request: Request) = commonRequest(request)

    open fun protocol(protocol: Protocol) = commonProtocol(protocol)

    open fun code(code: Int) = commonCode(code)

    open fun message(message: String) = commonMessage(message)

    open fun handshake(handshake: Handshake?) =
      apply {
        this.handshake = handshake

    } else {
      eventSequence.forEach loop@{
        when (e.closes(it)) {
          null -> return // no open event
          true -> return // found open event
          false -> return@loop // this is not the open event so continue
        }
      }
      Assertions.fail<Any>("event $e without matching start event")
    }
  }

  override fun connectStart(

  /**
   * Invoked when an event source has been accepted by the remote peer and may begin transmitting
   * events.
   */
  open fun onOpen(
    eventSource: EventSource,
    response: Response,
  ) {
  }

  /**
   * TODO description.
   */
  open fun onEvent(
    eventSource: EventSource,
    id: String?,
    type: String?,
    data: String,
  ) {
  }

  /**