* imposes both obligations and limits on the client application.
 *
 * ### The response body must be closed.
 *
 * Each response body is backed by a limited resource like a socket (live network responses) or
 * an open file (for cached responses). Failing to close the response body will leak resources and
 * may ultimately cause the application to slow down or crash.
 *

      promisedStreamId: Int,
      requestHeaders: List<Header>,
    )

    /**
     * HTTP/2 only. Expresses that resources for the connection or a client- initiated stream are
     * available from a different network location or protocol configuration.
     *
     * See [alt-svc][alt_svc].
     *
     * [alt_svc]: http://tools.ietf.org/html/draft-ietf-httpbis-alt-svc-01
     *

  @Test
  fun webSocketAndNetworkInterceptors() {
    client =
      client.newBuilder()
        .addNetworkInterceptor(
          Interceptor { chain: Interceptor.Chain? ->
            throw AssertionError() // Network interceptors don't execute.
          },
        )
        .build()
    webServer.enqueue(
      MockResponse.Builder()
        .webSocketUpgrade(serverListener)
        .build(),
    )

  var responder: (Request) -> Unit = {
    it.callback.onAnswer(listOf(), 0)
  }

  data class Request(
    val network: Network?,
    val domain: String,
    val nsType: Int,
    val flags: Int,
    val callback: DnsResolver.Callback<List<InetAddress>>,
  )

  @Implementation
  fun query(
    network: Network?,
    domain: String,
    nsType: Int,
    flags: Int,
    executor: Executor,

    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)
    }
  }

Content-Length: 1759
Connection: keep-alive
```

The network requests also contain more data, such as the `Accept-Encoding: gzip` header added by OkHttp to advertise support for response compression. The network interceptor's `Chain` has a non-null `Connection` that can be used to interrogate the IP address and TLS configuration that were used to connect to the webserver.

### Choosing between application and network interceptors

      System.out.println("Response 1 response:          " + response1);
      System.out.println("Response 1 cache response:    " + response1.cacheResponse());
      System.out.println("Response 1 network response:  " + response1.networkResponse());
    }

    String response2Body;
    try (Response response2 = client.newCall(request).execute()) {

 * Response caching avoids the network completely for repeat requests.

OkHttp perseveres when the network is troublesome: it will silently recover from common connection
problems. If your service has multiple IP addresses, OkHttp will attempt alternate addresses if the
first connect fails. This is necessary for IPv4+IPv6 and services hosted in redundant data

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="okhttp.android.test">

  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

   */
  open fun onClosed(
    webSocket: WebSocket,
    code: Int,
    reason: String,
  ) {
  }

  /**
   * Invoked when a web socket has been closed due to an error reading from or writing to the
   * network. Both outgoing and incoming messages may have been lost. No further calls to this
   * listener will be made.
   */
  open fun onFailure(
    webSocket: WebSocket,
    t: Throwable,
    response: Response?,
  ) {