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()) {

   *
   * @param expectContinue true to return null if this is an intermediate response with a "100"
   * response code. Otherwise this method never returns null.
   */
  @Throws(IOException::class)
  fun readResponseHeaders(expectContinue: Boolean): Response.Builder?

  @Throws(IOException::class)
  fun reportedContentLength(response: Response): Long

  @Throws(IOException::class)

 *  2. Open a sink to write the request body. Either [known][newKnownLengthSink] or
 *     [chunked][newChunkedSink].
 *  3. Write to and then close that sink.
 *  4. [Read response headers][readResponseHeaders].
 *  5. Open a source to read the response body. Either [fixed-length][newFixedLengthSource],
 *     [chunked][newChunkedSource] or [unknown][newUnknownLengthSource].
 *  6. Read from and close that source.
 *

  }

  override fun flushRequest() {
    http2Connection.flush()
  }

  override fun finishRequest() {
    stream!!.sink.close()
  }

  override fun readResponseHeaders(expectContinue: Boolean): Response.Builder? {
    val stream = stream ?: throw IOException("stream wasn't created")
    val headers = stream.takeHeaders(callerIsIdle = expectContinue)

    }
  }

  fun responseHeadersStart() {
    eventListener.responseHeadersStart(call)
  }

  @Throws(IOException::class)
  fun readResponseHeaders(expectContinue: Boolean): Response.Builder? {
    try {
      val result = codec.readResponseHeaders(expectContinue)
      result?.initExchange(this)
      return result
    } catch (e: IOException) {
      eventListener.responseFailed(call, e)

      tunnelCodec.writeRequest(nextRequest.headers, requestLine)
      tunnelCodec.finishRequest()
      val response =
        tunnelCodec
          .readResponseHeaders(false)!!
          .request(nextRequest)
          .build()
      tunnelCodec.skipConnectBody(response)

      when (response.code) {
        HttpURLConnection.HTTP_OK -> return null

HSPLokhttp3/internal/connection/Exchange;->openResponseBody(Lokhttp3/Response;)Lokhttp3/ResponseBody;
HSPLokhttp3/internal/connection/Exchange;->readResponseHeaders(Z)Lokhttp3/Response$Builder;
HSPLokhttp3/internal/connection/Exchange;->responseHeadersStart()V
HSPLokhttp3/internal/connection/Exchange;->writeRequestHeaders(Lokhttp3/Request;)V