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")
        }

      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()

      assertThat(response.protocol).isEqualTo(Protocol.HTTP_2)
    }
  }

  @Test
  fun testOkHttpSecureProxiedHttp1() {
    testRequest {
      val client =
        OkHttpClient.Builder()
          .trustMockServer()
          .proxy(Proxy(Proxy.Type.HTTP, it.remoteAddress()))
          .protocols(listOf(Protocol.HTTP_1_1))
          .build()

      val response =

import java.net.ProtocolException
import okhttp3.Protocol
import okhttp3.Response
import okio.IOException

/** An HTTP response status line like "HTTP/1.1 200 OK". */
class StatusLine(
  @JvmField val protocol: Protocol,
  @JvmField val code: Int,
  @JvmField val message: String,
) {
  override fun toString(): String {
    return buildString {
      if (protocol == Protocol.HTTP_1_0) {
        append("HTTP/1.0")
      } else {

        connectTls(sslSocket, connectionSpec)
        user.secureConnectEnd(handshake)
      } else {
        socket = rawSocket
        protocol =
          when {
            Protocol.H2_PRIOR_KNOWLEDGE in route.address.protocols -> Protocol.H2_PRIOR_KNOWLEDGE
            else -> Protocol.HTTP_1_1
          }
      }

      val connection =
        RealConnection(
          taskRunner = taskRunner,

    private static URLStreamHandler getDefaultStreamHandler ( String protocol ) throws IOException {
        synchronized ( PROTOCOL_HANDLERS ) {
            URLStreamHandler handler = PROTOCOL_HANDLERS.get(protocol);
            if ( handler != null )
                return handler;
            if ( factory != null ) {
                handler = factory.createURLStreamHandler(protocol);
            }
            if ( handler == null ) {

   */
  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"
      }

          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) {

      super.configureTlsExtensions(sslSocket, hostname, protocols)
    }
  }

  override fun getSelectedProtocol(sslSocket: SSLSocket): String? =
    if (sslSocket is BCSSLSocket) {
      when (val protocol = (sslSocket as BCSSLSocket).applicationProtocol) {
        // Handles both un-configured and none selected.
        null, "" -> null
        else -> protocol
      }
    } else {
      super.getSelectedProtocol(sslSocket)
    }

    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 =