*/
  @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()

assertEquals("application/json; charset=utf-8", request.getHeader("Content-Type"));
assertEquals("{}", request.getBody().readUtf8());
```

#### Dispatcher

By default MockWebServer uses a queue to specify a series of responses. Use a
Dispatcher (`import okhttp3.mockwebserver.Dispatcher`) to handle requests using another policy. One natural policy is to
dispatch on the request path.

    private class AuthenticatorNone : Authenticator {
      override fun authenticate(
        route: Route?,
        response: Response,
      ): Request? = null
    }

    /** An authenticator that uses the java.net.Authenticator global authenticator. */
    @JvmField
    val JAVA_NET_AUTHENTICATOR: Authenticator = JavaNetAuthenticator()
  }

This [sample factory](https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PrintEvents.java) creates a unique ID for each call and uses that ID to differentiate calls in log messages.

```java
class PrintingEventListener extends EventListener {
  public static final Factory FACTORY = new Factory() {
    final AtomicLong nextCallId = new AtomicLong(1L);

    }

    assertThat(server.requestCount).isEqualTo(0)

    // Confirm that the connection pool was not corrupted by making another call. This doesn't use
    // makeSimpleCall() because it uses the MockResponse enqueued above.
    val callB = client.newCall(Request(server.url("/")))
    callB.execute().use { response ->
      assertThat(response.body.string()).isEqualTo("abc")
    }
  }

    This regression was introduced in OkHttp 4.3.0.
 *  Fix: Don't crash with an `IllegalArgumentException` when using custom trust managers on
    Android 10. Android uses reflection to look up a magic `checkServerTrusted()` method and we
    didn't have it.
 *  Fix: Explicitly specify the remote server name when making HTTPS connections on Android 5. In

same underlying TCP socket connection. Sharing a connection has substantial performance benefits: lower latency, higher throughput (due to [TCP slow start](https://www.igvita.com/2011/10/20/faster-web-vs-tcp-slow-start/)) and conserved battery. OkHttp uses a [ConnectionPool](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-connection-pool/) that automatically reuses HTTP/1.x connections and multiplexes HTTP/2 connections.

In OkHttp some fields of the address come from the URL (scheme, hostname,...

   used.
 * Fix 1.5.0 regression where conditional cache responses could corrupt the
   connection pool.


## Version 1.5.0

_2014-03-07_


##### OkHttp no longer uses the default SSL context.

Applications that want to use the global SSL context with OkHttp should configure their
OkHttpClient instances with the following:

```java

  /**
   * Invoked when a call is assigned a particular connection.
   */
  open fun connectionAcquired(
    connection: Connection,
    call: Call,
  ) {}

  /**
   * Invoked when a call no longer uses a connection.
   */
  open fun connectionReleased(
    connection: Connection,
    call: Call,
  ) {}

  /**
   * Invoked when a connection is marked for no new exchanges.
   */

Debug Logging
=============

OkHttp has internal APIs to enable debug logging. It uses the `java.util.logging` API which can be
tricky to configure. As a shortcut, you can paste [OkHttpDebugLogging.kt]. Then enable debug logging
for whichever features you need:

```
OkHttpDebugLogging.enableHttp2()
OkHttpDebugLogging.enableTaskRunner()
```

### Activating on Android

```
$ adb shell setprop log.tag.okhttp.Http2 DEBUG