)
  }

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

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

  @Test fun ipv4Only() {
    val result =
      reorderForHappyEyeballs(
        listOf(
          ipv4_10_0_0_6,
          ipv4_10_0_0_1,
          ipv4_10_0_0_4,
        ),

 *  - Async DNS split by IP class
 *  - Stateful handling of connectivity results
 *  - The prioritisation of addresses
 *
 * https://datatracker.ietf.org/doc/html/rfc8305#section-4
 */
fun reorderForHappyEyeballs(addresses: List<InetAddress>): List<InetAddress> {
  if (addresses.size < 2) {
    return addresses
  }

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

          result
        }

      // Try each address for best behavior in mixed IPv4/IPv6 environments.
      val orderedAddresses =
        when {
          fastFallback -> reorderForHappyEyeballs(addresses)
          else -> addresses
        }

      for (inetAddress in orderedAddresses) {
        mutableInetSocketAddresses += InetSocketAddress(inetAddress, socketPort)
      }
    }
  }