}

        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 -> {

            sslSocketFactory(
              sslSocketFactory,
              handshakeCertificates.trustManager,
            )

            when (socketMode.protocol) {
              HTTP_2 -> protocols(listOf(HTTP_2, HTTP_1_1))
              HTTP_1_1 -> protocols(listOf(HTTP_1_1))
              else -> TODO()
            }

            val serverSslSocketFactory =

    /**
     * When [protocols][MockWebServer.protocols] include [HTTP_2][okhttp3.Protocol], this attaches a
     * pushed stream to this response.
     */
    public fun addPush(promise: PushPromise): Builder =
      apply {
        this.pushPromises_ += promise
      }

    /**
     * When [protocols][MockWebServer.protocols] include [HTTP_2][okhttp3.Protocol], this pushes
     * [settings] before writing the response.

      .cache(Cache(fileSystem, "/cache/".toPath(), Long.MAX_VALUE))
      .build()

  @Test
  fun trailersHttp1() {
    trailers(Protocol.HTTP_1_1)
  }

  @Test
  fun trailersHttp2() {
    trailers(Protocol.HTTP_2)
  }

  private fun trailers(protocol: Protocol) {
    enableProtocol(protocol)

    server.enqueue(
      MockResponse
        .Builder()
        .addHeader("h1", "v1")

        .eventListenerFactory(clientTestRule.wrap(eventRecorder))
        .build()
  }

  @RepeatedTest(100)
  fun http2OneBadHostOneGoodNoRetryOnConnectionFailure() {
    enableProtocol(Protocol.HTTP_2)

    val request = Request(server1.url("/"))

    server1.enqueue(refusedStream)
    server2.enqueue(bodyResponse)

    dns[server1.hostName] = listOf(ipv6, ipv4)
    socketFactory[ipv6] = server1.socketAddress

          .build(),
      )
    assertFailsWith<ProtocolException> {
      call.execute()
    }
  }

  @Test
  fun trueDuplexClientWritesFirst() {
    enableProtocol(Protocol.HTTP_2)
    val body =
      MockSocketHandler()
        .receiveRequest("request A\n")
        .sendResponse("response B\n")
        .receiveRequest("request C\n")
        .sendResponse("response D\n")

                }
              },
            ),
          ).build()

      val response = client.newCall(request).execute()

      response.use {
        assertEquals(Protocol.HTTP_2, response.protocol)
        assertEquals(200, response.code)
        // see https://github.com/google/conscrypt/blob/b9463b2f74df42d85c73715a5f19e005dfb7b802/android/src/main/java/org/conscrypt/Platform.java#L613
        when {

    }

  @Test
  fun successfulEmptyH2CallEventSequence() {
    enableTlsWithTunnel()
    server.protocols = Arrays.asList(Protocol.HTTP_2, Protocol.HTTP_1_1)
    server.enqueue(MockResponse())
    assertSuccessfulEventOrder(matchesProtocol(Protocol.HTTP_2), emptyBody = true)
    assertBytesReadWritten(
      eventRecorder,
      CoreMatchers.any(Long::class.java),
      null,
      greaterThan(0L),

    val response = client.newCall(request).execute()

    response.use {
      assertEquals(200, response.code)
      assertEquals(TlsVersion.TLS_1_3, response.handshake?.tlsVersion)
      assertEquals(Protocol.HTTP_2, response.protocol)

      assertThat(response.exchangeAccessor!!.connectionAccessor.socket())
        .isInstanceOf<SSLSocketImpl>()
    }
  }

  @Test
  fun testSupportedProtocols() {

There is no plan to remove these settings.

### Go 1.6

Go 1.6 introduced transparent support for HTTP/2,
controlled by the [`http2client`, `http2server`, and `http2debug` settings](/pkg/net/http/#hdr-HTTP_2).
There is no plan to remove these settings.

### Go 1.5

Go 1.5 introduced a pure Go DNS resolver,
controlled by the [`netdns` setting](/pkg/net/#hdr-Name_Resolution).