}
  }
  return result.readUtf8()
}

/**
 * Returns the canonical address for [address]. If [address] is an IPv6 address that is mapped to an
 * IPv4 address, this returns the IPv4-mapped address. Otherwise, this returns [address].
 *
 * https://en.wikipedia.org/wiki/IPv6#IPv4-mapped_IPv6_addresses
 */
internal fun canonicalizeInetAddress(address: ByteArray): ByteArray {
  return when {

  private val hostAddresses: MutableMap<String, List<InetAddress>> = mutableMapOf()
  private val requestedHosts: MutableList<String> = mutableListOf()
  private var nextAddress = 0xff000064L // 255.0.0.100 in IPv4; ::ff00:64 in IPv6.

  /** Sets the results for `hostname`.  */
  operator fun set(
    hostname: String,
    addresses: List<InetAddress>,
  ): FakeDns {
    hostAddresses[hostname] = addresses
    return this
  }

  }

  /** No SNI for literal IPv6 addresses. */
  @Test
  fun ipv6() {
    val recordedRequest = requestToHostnameViaProxy("2607:f8b0:400b:804::200e")
    assertThat(recordedRequest.requestUrl!!.host).isEqualTo("2607:f8b0:400b:804::200e")
    assertThat(recordedRequest.handshakeServerNames).isEmpty()
  }

  /** No SNI for literal IPv4 addresses. */
  @Test
  fun ipv4() {

    assertThat(routeSelector.hasNext()).isTrue()
    val (ipv4_1, ipv4_2) = dns.allocate(2)
    val (ipv6_1, ipv6_2) = dns.allocateIpv6(2)
    dns[uriHost] = listOf(ipv4_1, ipv4_2, ipv6_1, ipv6_2)

    val selection = routeSelector.next()
    assertThat(selection.routes.map { it.socketAddress.address }).containsExactly(
      ipv4_1,
      ipv4_2,
      ipv6_1,
      ipv6_2,
    )
  }

 * [system DNS service][SYSTEM], which is the default. Some applications may provide their own
 * implementation to use a different DNS server, to prefer IPv6 addresses, to prefer IPv4 addresses,
 * or to force a specific known IP address.
 *
 * Implementations of this interface must be safe for concurrent use.
 */
fun interface Dns {
  /**

import org.junitpioneer.jupiter.RetryingTest
import org.opentest4j.TestAbortedException

/**
 * This test binds two different web servers (IPv4 and IPv6) to the same port, but on different
 * local IP addresses. Requests made to `127.0.0.1` will reach the IPv4 server, and requests made to
 * `::1` will reach the IPv6 server.
 *
 * By orchestrating two different servers with the same port but different IP addresses, we can

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

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

    dns[server1.hostName] = listOf(ipv6, ipv4)
    socketFactory[ipv6] = server1.inetSocketAddress
    socketFactory[ipv4] = server2.inetSocketAddress

    client =
      client.newBuilder()
        .fastFallback(false)
        .apply {
          retryOnConnectionFailure = false
        }

          ipv4_10_0_0_6,
          ipv4_10_0_0_1,
          ipv4_10_0_0_4,
          ipv6_ab,
          ipv6_fc,
        ),
      )

    assertThat(result).isEqualTo(
      listOf(ipv6_ab, ipv4_10_0_0_6, ipv6_fc, ipv4_10_0_0_1, ipv4_10_0_0_4),
    )
  }

  @Test fun ipv6Only() {
    val result = reorderForHappyEyeballs(listOf(ipv6_ab, ipv6_fc))

    assertThat(result).isEqualTo(
      listOf(ipv6_ab, ipv6_fc),

fun reorderForHappyEyeballs(addresses: List<InetAddress>): List<InetAddress> {
  if (addresses.size < 2) {
    return addresses
  }

  val (ipv6, ipv4) = addresses.partition { it is Inet6Address }

  return if (ipv6.isEmpty() || ipv4.isEmpty()) {
    addresses
  } else {
    interleave(ipv6, ipv4)
  }

        },
      )
    }
  }

  @ExperimentalOkHttpApi
  companion object {
    @RequiresApi(Build.VERSION_CODES.Q)
    val IPv4 = AndroidAsyncDns(dnsClass = AsyncDns.DnsClass.IPV4)

    @RequiresApi(Build.VERSION_CODES.Q)
    val IPv6 = AndroidAsyncDns(dnsClass = AsyncDns.DnsClass.IPV6)
  }