assertThat(listener.recordedEventTypes().filter { it == "ConnectStart" }).hasSize(1)
    assertThat(listener.recordedEventTypes().filter { it == "ConnectFailed" }).hasSize(0)
  }

  @Test
  fun callIpv6WhenBothServersAreReachable() {
    // Flip DNS results to prefer IPv6.
    dnsResults =
      listOf(
        localhostIpv6,
        localhostIpv4,
      )
    serverIpv4.enqueue(