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

     *
     * @param protocol the protocol name to add (without colon suffix)
     */
    public void addWebProtocol(final String protocol) {
        final String prefix = protocol + ":";
        if (stream(webProtocols).get(stream -> stream.anyMatch(s -> s.equals(prefix)))) {
            logger.debug("Web protocols already contains: protocol={}", protocol);
            return;
        }

pkg net/http, method (*Protocols) SetHTTP1(bool) #67814
pkg net/http, method (*Protocols) SetHTTP2(bool) #67814
pkg net/http, method (*Protocols) SetUnencryptedHTTP2(bool) #67816
pkg net/http, method (Protocols) HTTP1() bool #67814
pkg net/http, method (Protocols) HTTP2() bool #67814
pkg net/http, method (Protocols) String() string #67814
pkg net/http, method (Protocols) UnencryptedHTTP2() bool #67816

      .assertSuccessful()
      .assertCode(200)
  }

  private fun enableProtocol(protocol: Protocol) {
    enableTls()
    client =
      client
        .newBuilder()
        .protocols(listOf(protocol, Protocol.HTTP_1_1))
        .build()
    server1.protocols = client.protocols
    server2.protocols = client.protocols
  }

  private fun enableTls() {
    client =
      client

Kotlin does have properties and we take advantage of them in OkHttp.

 * **Address**: certificatePinner, connectionSpecs, dns, hostnameVerifier, protocols, proxy,
   proxyAuthenticator, proxySelector, socketFactory, sslSocketFactory, url
 * **Cache**: directory
 * **CacheControl**: immutable, maxAgeSeconds, maxStaleSeconds, minFreshSeconds, mustRevalidate,

   */
  public var protocols: List<Protocol> = immutableListOf(Protocol.HTTP_2, Protocol.HTTP_1_1)
    set(value) {
      val protocolList = value.toImmutableList()
      require(Protocol.H2_PRIOR_KNOWLEDGE !in protocolList || protocolList.size == 1) {
        "protocols containing h2_prior_knowledge cannot use other protocols: $protocolList"
      }

   *
   * For cipher suites, at least one of the [required cipher suites][cipherSuites] must match the
   * socket's enabled cipher suites. If there are no required cipher suites the socket must have at
   * least one cipher suite enabled.
   *
   * For protocols, at least one of the [required protocols][tlsVersions] must match the socket's
   * enabled protocols.

  }

  @Test
  fun testH2PriorKnowledgeServerFallback() {
    try {
      server.protocols = Arrays.asList(Protocol.H2_PRIOR_KNOWLEDGE, Protocol.HTTP_1_1)
      fail<Any>()
    } catch (expected: IllegalArgumentException) {
      assertThat(expected.message).isEqualTo(
        "protocols containing h2_prior_knowledge cannot use other protocols: " +
          "[h2_prior_knowledge, http/1.1]",
      )
    }
  }

  @Test

      response!!.closeQuietly()
    }
  }

  private fun enableHttps() {
    enableHttpsAndAlpn(Protocol.HTTP_1_1)
  }

  private fun enableHttp2() {
    platform.assumeHttp2Support()
    enableHttpsAndAlpn(Protocol.HTTP_2, Protocol.HTTP_1_1)
  }

  private fun enableHttpsAndAlpn(vararg protocols: Protocol) {
    client =
      client
        .newBuilder()
        .sslSocketFactory(

    dnsResults =
      listOf(
        localhostIpv4,
        localhostIpv6,
        TestUtil.UNREACHABLE_ADDRESS_IPV4.address,
      )
    serverIpv4.protocols = listOf(Protocol.H2_PRIOR_KNOWLEDGE)
    serverIpv6.protocols = listOf(Protocol.H2_PRIOR_KNOWLEDGE)

    // Yield the first IP address so the second IP address completes first.
    val firstConnectLatch = CountDownLatch(1)
    val socketFactory =