var addresses1 []Address
	if err := DB.Model(&person).Association("Addresses").Find(&addresses1); err != nil || len(addresses1) != 2 {
		t.Fatalf("Failed to find address, got error %v, length: %v", err, len(addresses1))
	}

	if err := DB.Model(&person).Association("Addresses").Delete(&person.Addresses[0]); err != nil {
		t.Fatalf("Failed to delete address, got error %v", err)
	}

	if len(person.Addresses) != 1 {

/**
 * 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
  }

    /**
     * Retrieve all addresses of a host by it's address. NetBIOS hosts can
     * have many names for a given IP address. The name and IP address make the
     * NetBIOS address. This provides a way to retrieve the other names for a
     * host with the same IP address.
     *
     * @param host
     *            hostname to lookup all addresses for
     * @return resolved addresses
     * @throws java.net.UnknownHostException

   */
  @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(

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])
  }

  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
  }

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.
 *

    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>()

	"github.com/minio/minio/internal/logger"
	xnet "github.com/minio/pkg/v3/net"
)

var (
	// IPv4 addresses of localhost.
	localIP4 = mustGetLocalIP4()

	// IPv6 addresses of localhost.
	localIP6 = mustGetLocalIP6()

	// List of all local loopback addresses.
	localLoopbacks = mustGetLocalLoopbacks()
)

// mustSplitHostPort is a wrapper to net.SplitHostPort() where error is assumed to be a fatal.

They're also concrete: each URL identifies a specific path (like `/square/okhttp`) and query (like `?q=sharks&lang=en`). Each webserver hosts many URLs.

### [Addresses](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-address/)

Addresses specify a webserver (like `github.com`) and all of the **static** configuration necessary to connect to that server: the port number, HTTPS settings, and preferred network protocols (like HTTP/2).