/**
 * Implementation of HappyEyeballs Sorting Addresses.
 *
 * The current implementation does not address any of:
 *  - 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 result = proxies[nextProxyIndex++]
    resetNextInetSocketAddress(result)
    return result
  }

  /** Prepares the socket addresses to attempt for the current proxy or host. */
  @Throws(IOException::class)
  private fun resetNextInetSocketAddress(proxy: Proxy) {
    // Clear the addresses. Necessary if getAllByName() below throws!
    val mutableInetSocketAddresses = mutableListOf<InetSocketAddress>()

import okhttp3.Dns.Companion.SYSTEM

/**
 * A domain name service that resolves IP addresses for host names. Most applications will use the
 * [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.
 *

import okhttp3.Dns

/**
 * A network that always resolves two IP addresses per host. Use this when testing route selection
 * fallbacks to guarantee that a fallback address is available.
 */
class DoubleInetAddressDns : Dns {
  override fun lookup(hostname: String): List<InetAddress> {
    val addresses = Dns.SYSTEM.lookup(hostname)
    return listOf(addresses[0], addresses[0])
  }

   * an IPv4 address or not.
   *
   * <p>IPv6 addresses are <b>coerced</b> to IPv4 addresses before being converted to integers.
   *
   * <p>As long as there are applications that assume that all IP addresses are IPv4 addresses and
   * can therefore be converted safely to integers (for whatever purpose) this function can be used
   * to handle IPv6 addresses as well until the application is suitably fixed.
   *

	if l.Address == "" && l.Port == 0 && l.Type == "" {
		return true
	}
	if l.Address != "" {
		addresses := retrieveListenerAdditionalAddresses(listener)
		addresses = append(addresses, retrieveListenerAddress(listener))
		found := false
		for _, address := range addresses {
			if strings.EqualFold(address, l.Address) {
				found = true
			}
		}
		if !found {
			return false
		}
	}

  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
  }

  /** Clears the results for `hostname`.  */
  fun clear(hostname: String): FakeDns {
    hostAddresses.remove(hostname)
    return this
  }

		}
	}

	return ipList
}

// mustGetLocalIP4 returns IPv4 addresses of localhost.  It panics on error.
func mustGetLocalIP4() (ipList set.StringSet) {
	ipList = set.NewStringSet()
	for _, ip := range mustGetLocalIPs() {
		if ip.To4() != nil {
			ipList.Add(ip.String())
		}
	}
	return
}

// mustGetLocalIP6 returns IPv6 addresses of localhost.  It panics on error.
func mustGetLocalIP6() (ipList set.StringSet) {

   */
  @ExperimentalOkHttpApi
  interface Callback {
    /**
     * Return addresses for a dns query for a single class of IPv4 (A) or IPv6 (AAAA).
     * May be an empty list indicating that the host is unreachable.
     */
    fun onResponse(
      hostname: String,
      addresses: List<InetAddress>,
    )

    /**
     * Returns an error for the DNS query.
     */
    fun onFailure(

        executor,
        null,
        object : DnsResolver.Callback<List<InetAddress>> {
          override fun onAnswer(
            addresses: List<InetAddress>,
            rCode: Int,
          ) {
            callback.onResponse(hostname, addresses)
          }

          override fun onError(e: DnsResolver.DnsException) {
            callback.onFailure(
              hostname,