} catch (e: IOException) {
      eventListener.requestFailed(call, e)
      trackFailure(e)
      throw e
    }
  }

  @Throws(IOException::class)
  fun finishRequest() {
    try {
      codec.finishRequest()
    } catch (e: IOException) {
      eventListener.requestFailed(call, e)
      trackFailure(e)
      throw e
    }
  }

  fun responseHeadersStart() {

   * CONNECT tunnels. Note that CONNECT tunnels are significantly less capable than connections.
   */
  interface Carrier {
    val route: Route

    fun trackFailure(
      call: RealCall,
      e: IOException?,
    )

    fun noNewExchanges()

    fun cancel()
  }

  companion object {
    /**

      user.acquireConnectionNoEvents(connection)
    }

    user.connectionAcquired(connection)
    user.connectionConnectionAcquired(connection)
    return connection
  }

  override fun trackFailure(
    call: RealCall,
    e: IOException?,
  ) {
    // Do nothing.
  }

  override fun noNewExchanges() {
    // Do nothing.
  }

  override fun cancel() {
    canceled = true

  }

  /**
   * Track a failure using this connection. This may prevent both the connection and its route from
   * being used for future exchanges.
   */
  override fun trackFailure(
    call: RealCall,
    e: IOException?,
  ) {
    var noNewExchangesEvent = false
    withLock {
      if (e is StreamResetException) {
        when {