}

    @Test
    void testAddIPAddresses() throws Exception {
        InetAddress ipv4 = InetAddress.getByName("192.168.1.100");
        InetAddress ipv6 = InetAddress.getByName("2001:db8::1");

        notification.addNewIPAddress(ipv4);
        notification.addNewIPAddress(ipv6);
        notification.addOldIPAddress(ipv4);

        List<WitnessNotification.WitnessIPAddress> newAddresses = notification.getNewIPAddresses();

internal 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)
  }

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

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

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

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

        }

        /**
         * Checks if this is an IPv4 address.
         *
         * @return true if IPv4
         */
        public boolean isIPv4() {
            return (flags & IPV4) != 0;
        }

        /**
         * Checks if this is an IPv6 address.
         *
         * @return true if IPv6
         */
        public boolean isIPv6() {

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

     * @return IP address
     */
    public InetAddress getAddress() {
        return address;
    }

    /**
     * Check if this is an IPv6 address
     *
     * @return true if IPv6, false if IPv4
     */
    public boolean isIpv6() {
        return ipv6;
    }

    /**
     * Check if RSS is supported
     *
     * @return true if RSS capable
     */
    public boolean isRssCapable() {

    }
  }

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

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

_2022-02-01_

**This release introduces fast fallback to better support mixed IPv4+IPv6 networks.** Fast fallback
is what we're calling our implementation of Happy Eyeballs, [RFC 8305][rfc_8305]. With this
feature OkHttp will attempt both IPv6 and IPv4 connections concurrently, keeping whichever connects
first. Fast fallback gives IPv6 connections a 250 ms head start so IPv6 is preferred on networks
where it's available.

        
        if (rssCapable) score += 1000;   // Prefer RSS-capable
        if (rdmaCapable) score += 2000;  // Prefer RDMA-capable
        if (!ipv6) score += 100;         // Slight preference for IPv4
        
        return score;
    }
    
    private boolean checkRSSCapability() {
        // Platform-specific RSS detection
        // Simplified implementation
        try {

        private final int flags;
        
        public static final int IPV4 = 0x01;
        public static final int IPV6 = 0x02;
        
        public WitnessIPAddress(InetAddress address) {
            this.address = address;
            this.flags = address.getAddress().length == 4 ? IPV4 : IPV6;
        }
        
        public InetAddress getAddress() { return address; }