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) {

          // $0.05 worth of phone storage in 2020
          maxSize = 50L * 1024L * 1024L // 50 MiB
      ))
      .build()
```

## EventListener events

Cache Events are exposed via the EventListener API.  Typical scenarios are below.

### Cache Hit

In the ideal scenario the cache can fulfill the request without any conditional call to the network.

        var first = true
        client =
          client
            .newBuilder()
            .connectionSpecs(listOf(ConnectionSpec.RESTRICTED_TLS, ConnectionSpec.MODERN_TLS))
            .eventListener(
              object : EventListener() {
                override fun secureConnectEnd(
                  call: Call,
                  handshake: Handshake?,
                ) {
                  if (first) {

  fun connectionIsImmediatelyUnhealthy() {
    val listener: EventListener =
      object : EventListener() {
        override fun connectionAcquired(
          call: Call,
          connection: Connection,
        ) {
          connection.socket().closeQuietly()
        }
      }
    client =
      client
        .newBuilder()
        .eventListener(listener)
        .build()

        }

        @Override
        public <T extends java.util.EventListener> void addListener(T t) {
        }

        @Override
        public void addListener(Class<? extends java.util.EventListener> listenerClass) {
        }

        @Override
        public <T extends java.util.EventListener> T createListener(Class<T> clazz) {
            return null;
        }

        @Override

        }

        @Override
        public <T extends java.util.EventListener> void addListener(T t) {
        }

        @Override
        public void addListener(Class<? extends java.util.EventListener> listenerClass) {
        }

        @Override
        public <T extends java.util.EventListener> T createListener(Class<T> clazz) {
            return null;
        }

        @Override

        }

        @Override
        public <T extends java.util.EventListener> void addListener(T t) {
        }

        @Override
        public void addListener(Class<? extends java.util.EventListener> listenerClass) {
        }

        @Override
        public <T extends java.util.EventListener> T createListener(Class<T> clazz) {
            return null;
        }

        @Override