received followed by a cache hit or miss.  Critically in the cache hit scenario the server won’t send the response body.

The response will have non-null `cacheResponse` and `networkResponse`. The cacheResponse will be used as the top level
response only if the response code is HTTP/1.1 304 Not Modified.

 - CallStart
 - **CacheConditionalHit**
 - ConnectionAcquired
 - ... Standard Events...

 [CacheResponseJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/CacheResponse.java
 [CacheResponseKotlin]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/kt/CacheResponse.kt
 [CancelCallJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/CancelCall.java

    val builder: Response.Builder = response.newBuilder()
    val redirect: Boolean = response.isRedirect
    val networkResponse: Response? = response.networkResponse
    val cacheResponse: Response? = response.cacheResponse
    val priorResponse: Response? = response.priorResponse
    val challenges: List<Challenge> = response.challenges()
    val cacheControl: CacheControl = response.cacheControl

	public final fun -deprecated_sentRequestAtMillis ()J
	public final fun body ()Lokhttp3/ResponseBody;
	public final fun cacheControl ()Lokhttp3/CacheControl;
	public final fun cacheResponse ()Lokhttp3/Response;
	public final fun challenges ()Ljava/util/List;
	public fun close ()V
	public final fun code ()I
	public final fun handshake ()Lokhttp3/Handshake;

	public final fun -deprecated_sentRequestAtMillis ()J
	public final fun body ()Lokhttp3/ResponseBody;
	public final fun cacheControl ()Lokhttp3/CacheControl;
	public final fun cacheResponse ()Lokhttp3/Response;
	public final fun challenges ()Ljava/util/List;
	public fun close ()V
	public final fun code ()I
	public final fun handshake ()Lokhttp3/Handshake;

      .assertReceivedResponseAtMillis(request1SentAt, request1ReceivedAt)

    // Check the cached response. Its request contains only the saved Vary headers.
    cacheHit
      .cacheResponse()
      .assertCode(200)
      .assertHeaders(
        Headers
          .Builder()
          .add("ETag", "v1")
          .add("Cache-Control", "max-age=60")
          .add("Vary", "Accept-Charset")

    val response2 = client.newCall(Request(server.url("/"))).execute()
    assertThat(response2.body.string()).isEqualTo("second")
    assertThat(response2.cacheResponse).isNull()
  }

  @Test
  fun responseCachingAndRedirects() {
    server.enqueue(
      MockResponse
        .Builder()
        .addHeader("Last-Modified: " + formatDate(-1, TimeUnit.HOURS))

    requestCount++

    if (cacheStrategy.networkRequest != null) {
      // If this is a conditional request, we'll increment hitCount if/when it hits.
      networkCount++
    } else if (cacheStrategy.cacheResponse != null) {
      // This response uses the cache and not the network. That's a cache hit.
      hitCount++
    }
  }

  @Synchronized internal fun trackConditionalCacheHit() {
    hitCount++
  }

    )
    ```

 *  New: `Response.body` is now non-null. This was generally the case in OkHttp 4.x, but the Kotlin
    type declaration was nullable to support rare cases like the body on `Response.cacheResponse`,
    `Response.networkResponse`, and `Response.priorResponse`. In such cases the body is now
    non-null, but attempts to read its content will fail.