}

  /**
   * Revoke this exchange's access to streams. This is necessary when a follow-up request is
   * required but the preceding exchange hasn't completed yet.
   */
  fun detachWithViolence() {
    codec.cancel()
    call.messageDone(
      exchange = this,
      requestDone = true,
      responseDone = true,
      e = null,
    )
  }

  private fun trackFailure(e: IOException) {

        if ("100-continue".equals(request.header("Expect"), ignoreCase = true)) {
          exchange.flushRequest()
          responseBuilder = exchange.readResponseHeaders(expectContinue = true)
          exchange.responseHeadersStart()
          invokeStartEvent = false
        }
        if (responseBuilder == null) {
          if (requestBody.isDuplex()) {

  private val index: Int,
  internal val exchange: Exchange?,
  internal val request: Request,
  internal val connectTimeoutMillis: Int,
  internal val readTimeoutMillis: Int,
  internal val writeTimeoutMillis: Int,
) : Interceptor.Chain {
  private var calls: Int = 0

  internal fun copy(
    index: Int = this.index,
    exchange: Exchange? = this.exchange,
    request: Request = this.request,

internal var RealConnection.idleAtNsAccessor: Long
  get() = idleAtNs
  set(value) {
    idleAtNs = value
  }

internal val Response.exchangeAccessor: Exchange?
  get() = this.exchange

internal val Exchange.connectionAccessor: RealConnection
  get() = this.connection

  @Throws(IOException::class)
  override fun intercept(chain: Interceptor.Chain): Response {
    val realChain = chain as RealInterceptorChain
    val exchange = realChain.call.initExchange(realChain)
    val connectedChain = realChain.copy(exchange = exchange)
    return connectedChain.proceed(realChain.request)
  }

   * connection index, they also shared a socket connection.
   */
  public val connectionIndex: Int,
  /**
   * The index of this exchange on its HTTP connection. A request is uniquely identified by the
   * (connection index, exchange index) pair.
   */
  public val exchangeIndex: Int,
  /**
   * The TLS handshake of the connection that carried this request, or null if the request was

  val carrier: Carrier

  /** Returns true if the response body and (possibly empty) trailers have been received. */
  val isResponseComplete: Boolean

  /** The socket that carries this exchange. */
  val socket: Socket

  /** Returns an output stream where the request body can be streamed. */
  @Throws(IOException::class)
  fun createRequestBody(
    request: Request,
    contentLength: Long,
  ): Sink

      listener.sessionGranted(session);
    } catch (IOException e) {
      return new MockResponse()
          .setResponseCode(400)
          .setBody("code exchange failed: " + e.getMessage());
    }

    synchronized (this) {
      listeners.remove(state);
    }

    // Success!
    return new MockResponse()
        .setResponseCode(302)

 * **Exchange** carries a single HTTP request/response pair.

 * **ExchangeFinder** chooses which connection carries each exchange. Where possible it will use the same connection for all exchanges in a single call. It prefers reusing pooled connections over establishing new connections.      

package okhttp3

import okio.IOException

interface Callback {
  /**
   * Called when the request could not be executed due to cancellation, a connectivity problem or
   * timeout. Because networks can fail during an exchange, it is possible that the remote server
   * accepted the request before the failure.
   */
  fun onFailure(
    call: Call,
    e: IOException,
  )

  /**