@Throws(IOException::class)
  fun writeRequestHeaders(request: Request) {
    try {
      eventListener.requestHeadersStart(call)
      codec.writeRequestHeaders(request)
      eventListener.requestHeadersEnd(call, request)
    } catch (e: IOException) {
      eventListener.requestFailed(call, e)
      trackFailure(e)
      throw e
    }
  }

  @Throws(IOException::class)
  fun createRequestBody(