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")
        }

    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)
  }

          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 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,

 */
package okhttp3.internal.http

import okhttp3.OkHttpClient
import okhttp3.Protocol
import okhttp3.Request

object ExternalHttp2Example {
  @JvmStatic
  fun main(args: Array<String>) {
    val client =
      OkHttpClient.Builder()
        .protocols(listOf(Protocol.HTTP_2, Protocol.HTTP_1_1))
        .build()
    val call =
      client.newCall(
        Request.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 =

      assertThat(acceptedHostName).isEqualTo(hostname)

      if (socketMode.tlsExtensionMode == STANDARD) {
        assertThat(response.protocol).isEqualTo(socketMode.protocol)
      } else {
        assertThat(response.protocol).isEqualTo(HTTP_1_1)
      }
    }
  }

  companion object {
    @Suppress("unused")
    @JvmStatic
    fun connectionTypes(): List<SocketMode> =

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

                    if ("web".equalsIgnoreCase(protocolType)) {
                        addWebProtocol(protocol);
                    } else if ("file".equalsIgnoreCase(protocolType)) {
                        addFileProtocol(protocol);
                    } else {
                        logger.warn("Unknown protocol: {}", protocol);
                    }
                }
            } catch (final ClassNotFoundRuntimeException e) {