```kotlin
val client = OkHttpClient.Builder()
    .dns { hostname -> InetAddress.getAllByName(hostname).toList() }
    .build()
```

Kotlin calling OkHttp 4.x:

```kotlin
val client = OkHttpClient.Builder()
    .dns(object : Dns {
      override fun lookup(hostname: String) =
          InetAddress.getAllByName(hostname).toList()
    })
    .build()
```

SAM conversion impacts these APIs:

   */
  @Throws(UnknownHostException::class)
  fun lookup(hostname: String): List<InetAddress>

  companion object {
    /**
     * A DNS that uses [InetAddress.getAllByName] to ask the underlying operating system to
     * lookup IP addresses. Most custom [Dns] implementations should delegate to this instance.
     */
    @JvmField
    val SYSTEM: Dns = DnsSystem()

  }

  /** 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>()
    inetSocketAddresses = mutableInetSocketAddresses

    val socketHost: String
    val socketPort: Int

   * it to prefer IPv6.
   */
  private var dnsResults = listOf<InetAddress>()

  @BeforeEach
  internal fun setUp() {
    val inetAddresses = InetAddress.getAllByName("localhost")
    localhostIpv4 = inetAddresses.firstOrNull { it is Inet4Address }
      ?: throw TestAbortedException()
    localhostIpv6 = inetAddresses.firstOrNull { it is Inet6Address }
      ?: throw TestAbortedException()

   * | `http://a%20b:c%20d@host/`       | `"c d"`      |
   */
  @get:JvmName("password") val password: String,
  /**
   * The host address suitable for use with [InetAddress.getAllByName]. May be:
   *
   *  * A regular host name, like `android.com`.
   *
   *  * An IPv4 address, like `127.0.0.1`.
   *
   *  * An IPv6 address, like `::1`. Note that there are no square braces.
   *