)
    server.enqueue(
      MockResponse(body = "GHI"),
    )
    val call1 = client.newCall(Request(server.url("/")))
    val response1 = call1.execute()
    val call2 = client.newCall(Request(server.url("/")))
    val response2 = call2.execute()
    val call3 = client.newCall(Request(server.url("/")))
    val response3 = call3.execute()
    assertThat(response1.body.string()).isEqualTo("ABC")

    ```kotlin
      private val client = OkHttpClient()

      fun run() {
        val request = Request.Builder()
            .url("https://publicobject.com/helloworld.txt")
            .build()

        client.newCall(request).execute().use { response ->
          if (!response.isSuccessful) throw IOException("Unexpected code $response")

          for ((name, value) in response.headers) {
            println("$name: $value")
          }

    val call1 = localClient.newCall(Request(server.url("/")))

    call1.execute().use { response ->
      assertThat(response.body.string()).isEqualTo("Req1")
      assertThat(response.handshake).isNotNull()
      assertThat(response.protocol == Protocol.HTTP_1_1)
    }

    eventListener.closed = true

    val call2 = localClient.newCall(Request(server.url("/")))

    server.enqueue(MockResponse(body = "ghi"))
    client.newCall(Request.Builder().url(server.url("/a")).build()).enqueue(callback)
    callback.await(server.url("/a")).assertBody("abc")
    client.newCall(Request.Builder().url(server.url("/b")).build()).enqueue(callback)
    callback.await(server.url("/b")).assertBody("def")
    client.newCall(Request.Builder().url(server.url("/c")).build()).enqueue(callback)

      )
    serverIpv4.enqueue(
      MockResponse(body = "unexpected call to IPv4"),
    )
    serverIpv6.enqueue(
      MockResponse(body = "hello from IPv6"),
    )

    val call = client.newCall(Request(url))
    val response = call.execute()
    assertThat(response.body.string()).isEqualTo("hello from IPv6")

    // In the process we made one successful connection attempt.

  }

  @AfterEach
  fun tearDown() {
    executorService.shutdown()
  }

  @Test
  @Throws(IOException::class)
  fun http1DoesntSupportDuplex() {
    val call =
      client.newCall(
        Request
          .Builder()
          .url(server.url("/"))
          .post(AsyncRequestBody())
          .build(),
      )
    assertFailsWith<ProtocolException> {
      call.execute()
    }

        .header("Connection", "upgrade")
        .build()
    assertFailsWith<ProtocolException> {
      client.newCall(requestWithUpgrade).execute()
    }
  }

  @Test
  fun upgradesOnReusedConnection() {
    server.enqueue(MockResponse(body = "normal request"))
    client.newCall(Request(server.url("/"))).execute().use { response ->
      assertThat(response.body.string()).isEqualTo("normal request")
    }

  }

  @Test
  fun testTlsv13Works() {
    enableTls()

    server.enqueue(MockResponse(body = "abc"))

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

    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)

    assumeNotWindows()
    server.enqueue(
      MockResponse
        .Builder()
        .body("Hello!")
        .setHeader("Content-Type", PLAIN)
        .build(),
    )
    val response = client.newCall(request().build()).execute()
    assertThat(response.body).isNotNull()
    response.body.bytes()
    logRecorder
      .assertLogMatch(Regex("""callStart: Request\{method=GET, url=$url\}"""))

    }
  }

  @Test
  fun none() {
    server.enqueue(MockResponse())
    client.newCall(request().build()).execute()
    applicationLogs.assertNoMoreLogs()
    networkLogs.assertNoMoreLogs()
  }

  @Test
  fun basicGet() {
    setLevel(Level.BASIC)
    server.enqueue(MockResponse())
    client.newCall(request().build()).execute()
    applicationLogs
      .assertLogEqual("--> GET $url")