shadowDns.responder = {
      throw IllegalArgumentException("Network.fromNetworkHandle refusing to instantiate NETID_UNSET Network.")
    }

    val dns = AsyncDns.toDns(asyncDns)

    assertFailure {
      dns.lookup("google.invalid")
    }.apply {
      hasMessage("Network.fromNetworkHandle refusing to instantiate NETID_UNSET Network.")
      isInstanceOf(UnknownHostException::class)
    }
  }

### 域名

第一步我们要先**获取**一些**域名(Domain Name)**。 然后可以在 DNS 服务器（可能是你的同一家云服务商提供的）中配置它。

你可能拥有一个云服务器（虚拟机）或类似的东西，并且它会有一个<abbr title="That isn't Change">固定</abbr> **公共IP地址**。

在 DNS 服务器中，你可以配置一条记录（“A 记录”）以将 **你的域名** 指向你服务器的公共 **IP 地址**。

这个操作一般只需要在最开始执行一次。

/// tip

域名这部分发生在 HTTPS 之前，由于这一切都依赖于域名和 IP 地址，所以先在这里提一下。

///

### DNS

现在让我们关注真正的 HTTPS 部分。

首先，浏览器将通过 **DNS 服务器** 查询**域名的IP** 是什么，在本例中为 `someapp.example.com`。

 *
 *  * A DNS lookup failed
 *  * The configuration is incapable of carrying the request, such as when the client is configured
 *    to use `H2_PRIOR_KNOWLEDGE` but the URL's scheme is `https:`.
 *  * Preemptive proxy authentication failed.
 *
 * Planning failures are not necessarily fatal. For example, even if we can't DNS lookup the first

        .build(),
    )
    server.enqueue(MockResponse())
    val dns = FakeDns()
    dns["fakeurl"] = client.dns.lookup(server.hostName)
    dns["www.fakeurl"] = client.dns.lookup(server.hostName)
    client =
      client.newBuilder()
        .dns(dns)
        .build()
    val call =
      client.newCall(
        Request.Builder()

  // hostname of this endpoint. This field may be used by consumers of
  // endpoints to distinguish endpoints from each other (e.g. in DNS names).
  // Multiple endpoints which use the same hostname should be considered
  // fungible (e.g. multiple A values in DNS). Must be lowercase and pass DNS
  // Label (RFC 1123) validation.
  // +optional
  optional string hostname = 3;

	// and is 'true' when etcdConfig.PathPrefix is empty
	globalBucketFederation bool

	// Allocated DNS config wrapper over etcd client.
	globalDNSConfig dns.Store

	// GlobalKMS initialized KMS configuration
	GlobalKMS *kms.KMS

	// Common lock for various subsystems performing the leader tasks
	globalLeaderLock *sharedLock

	// Auto-Encryption, if enabled, turns any non-SSE-C request

   * address for all hosts, regardless of the actual number of IP addresses reported by DNS.
   */
  fun newClient(): OkHttpClient {
    var client = testClient
    if (client == null) {
      client =
        initialClientBuilder()
          .dns(SINGLE_INET_ADDRESS_DNS) // Prevent unexpected fallback addresses.

{
  "cniVersion": "0.3.1",
  "name": "istio-cni",
  "type": "istio-cni",
  "ipam": {},
  "dns": {},
  "plugin_log_level": "debug",
  "cni_agent_run_dir": "/path/to/kubeconfig",
  "ambient_enabled": false,
  "exclude_namespaces": [
    ""
  ]

        override fun peek(): MockResponse = TODO()

        override fun shutdown() = TODO()
      }
  }

  @Test
  fun dns() {
    var dns: Dns = Dns { TODO() }

    val system: Dns = Dns.SYSTEM
  }

  @Test
  fun eventListener() {
    val eventListener =
      object : EventListener() {
        override fun callStart(call: Call) = TODO()

{
  "cniVersion": "0.4.0",
  "name": "dbnet",
  "plugins": [
    {
      "args": {
        "labels": {
          "appVersion": "1.0"
        }
      },
      "bridge": "cni0",
      "dns": {
        "nameservers": [
          "10.1.0.1"
        ]
      },
      "ipam": {
        "gateway": "10.1.0.1",
        "subnet": "10.1.0.0/16",
        "type": "host-local"
      },
      "type": "bridge"
    },
    {