)
    val interceptor =
      Interceptor { chain: Interceptor.Chain ->
        // The network request has everything: User-Agent, Host, Accept-Encoding.
        val networkRequest = chain.request()
        assertThat(networkRequest.header("User-Agent")).isNotNull()
        assertThat(networkRequest.header("Host")).isEqualTo(
          server.hostName + ":" + server.port,
        )

 *     possible for shared exchanges to make requests to different host names! See
 *     [RealConnection.isEligible] for details.
 *
 *  3. Attempt plans from prior connect attempts for this call. These occur as either follow-ups to
 *     failed connect attempts (such as trying the next [ConnectionSpec]), or as attempts that lost
 *     a race in fast follow-up.
 *

    return connectionListener.recordedEventTypes()
  }

  companion object {
    /**
     * A network that resolves only one IP address per host. Use this when testing route selection
     * fallbacks to prevent the host machine's various IP addresses from interfering.
     */
    private val SINGLE_INET_ADDRESS_DNS =
      Dns { hostname ->
        val addresses = Dns.SYSTEM.lookup(hostname)

   * is running when that time is reached, that task is allowed to complete before this task is
   * started. Similarly the task will be delayed if the host lacks compute resources.
   *
   * @throws RejectedExecutionException if the queue is shut down and the task is not cancelable.
   */
  fun schedule(
    task: Task,
    delayNanos: Long = 0L,
  ) {

package okhttp3

import java.net.InetAddress
import java.net.UnknownHostException
import java.util.concurrent.CountDownLatch
import okio.IOException

/**
 * An async domain name service that resolves IP addresses for host names.
 *
 * The main implementations will typically be implemented using specific DNS libraries such as
 *  * Android DnsResolver
 *  * OkHttp DnsOverHttps
 *  * dnsjava Resolver
 *

            challenge.scheme,
            url.toUrl(),
            Authenticator.RequestorType.PROXY,
          )
        } else {
          Authenticator.requestPasswordAuthentication(
            url.host,
            proxy.connectToInetAddress(url, dns),
            url.port,
            url.scheme,
            challenge.realm,
            challenge.scheme,
            url.toUrl(),

        this.trustedCertificates += certificate
      }

    /**
     * Add all of the host platform's trusted root certificates. This set varies by platform
     * (Android vs. Java), by platform release (Android 4.4 vs. Android 9), and with user
     * customizations.
     *
     * Most TLS clients that connect to hosts on the public Internet should call this method.

        append(request.url)
      } else {
        append(requestPath(request.url))
      }
      append(" HTTP/1.1")
    }

  /**
   * Returns true if the request line should contain the full URL with host and port (like "GET
   * http://android.com/foo HTTP/1.1") or only the path (like "GET /foo HTTP/1.1").
   */
  private fun includeAuthorityInRequestLine(
    request: Request,
    proxyType: Proxy.Type,
  ): Boolean {

 *
 * By orchestrating two different servers with the same port but different IP addresses, we can
 * test what OkHttp does when both are reachable, or if only one is reachable.
 *
 * This test only runs on host machines that have both IPv4 and IPv6 addresses for localhost.
 */
@Timeout(30)
class FastFallbackTest {
  @RegisterExtension
  val clientTestRule = OkHttpClientTestRule()

      // If the domain is present, it must domain match. Otherwise we have a host-only cookie.
      val urlHost = url.host
      if (domain == null) {
        domain = urlHost
      } else if (!domainMatch(urlHost, domain)) {
        return null // No domain match? This is either incompetence or malice!
      }

      // If the domain is a suffix of the url host, it must not be a public suffix.
      if (urlHost.length != domain.length &&