HTTP_1_0.protocol -> HTTP_1_0
        HTTP_1_1.protocol -> HTTP_1_1
        H2_PRIOR_KNOWLEDGE.protocol -> H2_PRIOR_KNOWLEDGE
        HTTP_2.protocol -> HTTP_2
        SPDY_3.protocol -> SPDY_3
        QUIC.protocol -> QUIC
        else -> {
          // Support HTTP3 draft like h3-29
          if (protocol.startsWith(HTTP_3.protocol)) HTTP_3 else throw IOException("Unexpected protocol: $protocol")
        }

    clientTestRule.recordTaskRunner = true
    return clientTestRule
  }

  fun setUp(
    protocol: Protocol,
    server: MockWebServer,
  ) {
    this.server = server
    this.protocol = protocol
    platform.assumeNotOpenJSSE()
    if (protocol === Protocol.HTTP_2) {
      platform.assumeHttp2Support()
      server.useHttps(handshakeCertificates.sslSocketFactory())
      client =

    assertThat(statusLine.protocol).isEqualTo(Protocol.HTTP_1_1)
    assertThat(statusLine.code).isEqualTo(code)
  }

  @Test
  fun emptyMessage() {
    val version = 1
    val code = 503
    val statusLine = parse("HTTP/1.$version $code ")
    assertThat(statusLine.message).isEqualTo("")
    assertThat(statusLine.protocol).isEqualTo(Protocol.HTTP_1_1)
    assertThat(statusLine.code).isEqualTo(code)
  }

      OkHttpClient.Builder()
        .protocols(protocols as List<Protocol>)
    }.also { expected ->
      assertThat(expected.message).isEqualTo("protocols must not contain null")
    }
  }

  @Test fun spdy3IsRemovedFromProtocols() {
    val protocols =
      mutableListOf(
        Protocol.HTTP_1_1,
        Protocol.SPDY_3,
      )
    val client =
      OkHttpClient.Builder()

     * Returns the concatenation of 8-bit, length prefixed protocol names.
     * http://tools.ietf.org/html/draft-agl-tls-nextprotoneg-04#page-4
     */
    fun concatLengthPrefixed(protocols: List<Protocol>): ByteArray {
      val result = Buffer()
      for (protocol in alpnProtocolNames(protocols)) {
        result.writeByte(protocol.length)
        result.writeUtf8(protocol)
      }
      return result.readByteArray()
    }

        .build()
    val listener = loggingEventListenerFactory.create(call)
    listener.cacheConditionalHit(call, response)
    listener.cacheHit(call, response)
    listener.cacheMiss(call)
    listener.satisfactionFailure(call, response)
    logRecorder
      .assertLogMatch(Regex("""cacheConditionalHit: Response\{protocol=h2, code=200, message=, url=$url\}"""))

          val protocol = peerProtocols[i] as String
          if (protocol in protocols) {
            selected = protocol
            return selected
          }
        }
        selected = protocols[0] // On no intersection, try peer's first protocol.
        return selected
      } else if ((methodName == "protocolSelected" || methodName == "selected") && callArgs.size == 1) {

    assertThat(Protocol.SPDY_3.toString()).isEqualTo("spdy/3.1")
    assertThat(Protocol.HTTP_2.toString()).isEqualTo("h2")
    assertThat(Protocol.H2_PRIOR_KNOWLEDGE.toString())
      .isEqualTo("h2_prior_knowledge")
    assertThat(Protocol.QUIC.toString()).isEqualTo("quic")
    assertThat(Protocol.HTTP_3.toString()).isEqualTo("h3")
  }

   */
  private fun enableProtocol(protocol: Protocol) {
    enableTls()
    client =
      client.newBuilder()
        .protocols(listOf(protocol, Protocol.HTTP_1_1))
        .build()
    server.protocols = client.protocols
  }

  private fun enableTls() {
    client =
      client.newBuilder()
        .sslSocketFactory(

  private val http2Connection: Http2Connection,
) : ExchangeCodec {
  @Volatile private var stream: Http2Stream? = null

  private val protocol: Protocol =
    if (Protocol.H2_PRIOR_KNOWLEDGE in client.protocols) {
      Protocol.H2_PRIOR_KNOWLEDGE
    } else {
      Protocol.HTTP_2
    }

  @Volatile
  private var canceled = false

  override fun createRequestBody(
    request: Request,
    contentLength: Long,