.apply {
        listeners += ::onEvent
      }

  val eventListener: EventListener
    get() = eventListenerAdapter

  var eventCount = 0

  private fun onEvent(callEvent: CallEvent) {
    if (eventCount++ == 0) {
      eventRecorder.logEvent(callEvent)
      val next = EventListenerRelay(call, eventRecorder)
      call.addEventListener(next.eventListener)
    }
  }

0001 0.624 connectionReleased
0001 0.624 callEnd
```

The `EventListener.Factory` also makes it possible to limit metrics to a subset of calls. This one captures metrics on a random 10%:

```java
class MetricsEventListener extends EventListener {
  private static final Factory FACTORY = new Factory() {
    @Override public EventListener create(Call call) {
      if (Math.random() < 0.10) {

import java.util.concurrent.TimeUnit
import okhttp3.Call
import okhttp3.Connection
import okhttp3.Dispatcher
import okhttp3.EventListener
import okhttp3.Handshake
import okhttp3.HttpUrl
import okhttp3.OkHttpClient
import okhttp3.Protocol
import okhttp3.Request
import okhttp3.Response

/**
 * An OkHttp EventListener, which logs call events. Can be applied as an
 * [event listener factory][OkHttpClient.eventListenerFactory].
 *

  @StartStop
  private val server = MockWebServer()

  private var client =
    clientTestRule
      .newClientBuilder()
      .eventListener(listener)
      .build()

  class SocketClosingEventListener : EventListener() {
    var shouldClose: Boolean = false
    var lastSocket: Socket? = null

    override fun connectionAcquired(
      call: Call,
      connection: Connection,
    ) {

          listOf(
            ConnectionSpec
              .Builder(ConnectionSpec.MODERN_TLS)
              .supportsTlsExtensions(false)
              .build(),
          ),
        ).eventListener(
          object : EventListener() {
            override fun connectionAcquired(
              call: Call,
              connection: Connection,
            ) {
              val sslSocket = connection.socket() as SSLSocket

   */
  fun timeout(): Timeout

  /**
   * Configure this call to publish all future events to [eventListener], in addition to the
   * listeners configured by [OkHttpClient.Builder.eventListener] and other calls to this function.
   *
   * If this call is later [cloned][clone], [eventListener] will not be notified of its events.
   *

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.util.List;
import okhttp3.Call;
import okhttp3.Connection;
import okhttp3.EventListener;
import okhttp3.Handshake;
import okhttp3.HttpUrl;
import okhttp3.OkHttpClient;
import okhttp3.Protocol;
import okhttp3.Request;
import okhttp3.Response;

/**

  /**
   * An override to ignore the normal order that is enforced.
   * EventListeners added by Interceptors will not see all events.
   */
  private val enforceOrder: Boolean = true,
) {
  private val eventListenerAdapter =
    EventListenerAdapter()
      .apply {
        listeners += ::logEvent
      }

  val eventListener: EventListener
    get() = eventListenerAdapter

  /** Events that haven't yet been removed. */

}

public class okhttp3/logging/LoggingEventListener$Factory : okhttp3/EventListener$Factory {
	public fun <init> ()V
	public fun <init> (Lokhttp3/logging/HttpLoggingInterceptor$Logger;)V
	public synthetic fun <init> (Lokhttp3/logging/HttpLoggingInterceptor$Logger;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
	public fun create (Lokhttp3/Call;)Lokhttp3/EventListener;

  override fun isExecuted(): Boolean = error("unexpected")

  override fun isCanceled(): Boolean = error("unexpected")

  override fun timeout(): Timeout = error("unexpected")

  override fun addEventListener(eventListener: EventListener) = error("unexpected")

  override fun <T : Any> tag(type: KClass<T>): T? = error("unexpected")

  override fun <T> tag(type: Class<out T>): T? = error("unexpected")

  override fun <T : Any> tag(