serverListener.assertClosing(1000, "goodbye")

    // Confirm that the hard cancel occurred after 500 ms.
    clientListener.assertFailure()
    val elapsedUntilFailure = System.nanoTime() - closeAtNanos
    assertThat(TimeUnit.NANOSECONDS.toMillis(elapsedUntilFailure).toDouble())
      .isCloseTo(500.0, 250.0)

    // Close the server and confirm it saw what we expected.
    server.close(1000, null)

            else -> {
              connectionUser.acquireConnectionNoEvents(connection)
              true
            }
          }
        }
      if (!acquired) continue

      // Confirm the connection is healthy and return it.
      if (connection.isHealthy(doExtensiveHealthChecks)) return connection

      // In the second synchronized block, release the unhealthy acquired connection. We're also on

    )
    serverIpv4.enqueue(
      MockResponse(body = "this was the 2nd request on IPv4"),
    )
    serverIpv6.enqueue(
      MockResponse(body = "unexpected call to IPv6"),
    )

    // Confirm the retry succeeds on the same connection.
    val call = client.newCall(Request(url))
    val response = call.execute()
    assertThat(response.body.string()).isEqualTo("this was the 2nd request on IPv4")

    routeSelector = newRouteSelector(address)

    // Confirm we enumerate both proxies, giving preference to the route from ProxyB.
    val selection2 = routeSelector.next()
    dns.assertRequests(PROXY_A_HOST, PROXY_B_HOST)
    assertRoute(selection2.next(), address, proxyB, dns.lookup(PROXY_B_HOST, 0), PROXY_B_PORT)
    assertThat(selection2.hasNext()).isFalse()

    // Confirm the last selection contains the postponed route from ProxyA.

    taskRunner.lock.withLock {
      check(currentTask == TestThreadSerialTask)
      nanoTime = newTime
      yieldUntil(ResumePriority.AfterOtherTasks)
    }
  }

  /** Confirm all tasks have completed. Used by the test thread only. */
  fun assertNoMoreTasks() {
    taskRunner.assertThreadDoesntHoldLock()

    taskRunner.lock.withLock {
      assertThat(activeThreads).isEqualTo(0)
    }

    } catch (ioe: IOException) {
      assertThat(ioe).hasMessage("google.com")
      assertThat(ioe.cause!!).isInstanceOf<EOFException>()
    }
  }

  // TODO GET preferred order - with tests to confirm this
  // 1. successful fresh cached GET response
  // 2. unsuccessful (404, 500) fresh cached GET response
  // 3. successful network response
  // 4. successful stale cached GET response
  // 5. unsuccessful response

    assertThat(request.tag(String::class)).isSameAs(stringTag)

    // TODO check for Jvm or handle Long/long correctly
//    assertThat(request.tag(Long::class)).isSameAs(longTag)
  }

  /** Confirm that we don't accidentally share the backing map between objects. */
  @Test
  fun tagsAreImmutable() {
    val builder =
      Request.Builder()
        .url("https://square.com")

    assertThat(request.tag(UUID::class.java)).isSameAs(uuidTag)
    assertThat(request.tag(String::class.java)).isSameAs(stringTag)
    assertThat(request.tag(Long::class.javaObjectType)).isSameAs(longTag)
  }

  /** Confirm that we don't accidentally share the backing map between objects. */
  @Test
  fun tagsAreImmutable() {
    val builder =
      Request.Builder()
        .url("https://square.com")

    val parts =
      MultipartReader(
        boundary = "simple boundary",
        source = Buffer(),
      )

    assertFailsWith<EOFException> {
      parts.nextPart()
    }
  }

  /** Confirm that [MultipartBody] and [MultipartReader] can work together. */
  @Test fun `multipart round trip`() {
    val body =
      MultipartBody.Builder("boundary")
        .setType(MultipartBody.PARALLEL)

        .build()
    val certificate = heldCertificate.certificate
    assertThat(certificate.getSubjectX500Principal().name).isEqualTo(
      "CN=cash.app,OU=cash",
    )
  }

  /** Confirm golden values of encoded PEMs.  */
  @Test
  fun pems() {
    val keyFactory = KeyFactory.getInstance("RSA")
    val publicKeyBytes =
      (