document's age at the time it was served based on "Last-Modified". Default expiration dates aren't used for URIs
containing a query.

 - CallStart
 - **CacheHit**
 - CallEnd

### Cache Miss

Under a cache miss the normal request events are seen but an additional event shows the presence of the cache.

    Thread.sleep(10) // Make sure the timestamps are unique.
    val cacheHit =
      executeSynchronously(
        "/",
        "Accept-Language",
        "en-US",
        "Accept-Charset",
        "UTF-8",
      )

    // Check the merged response. The request is the application's original request.
    cacheHit
      .assertCode(200)
      .assertBody("A")
      .assertHeaders(

	public static final field NONE Lokhttp3/EventListener;
	public fun <init> ()V
	public fun cacheConditionalHit (Lokhttp3/Call;Lokhttp3/Response;)V
	public fun cacheHit (Lokhttp3/Call;Lokhttp3/Response;)V
	public fun cacheMiss (Lokhttp3/Call;)V
	public fun callEnd (Lokhttp3/Call;)V
	public fun callFailed (Lokhttp3/Call;Ljava/io/IOException;)V
	public fun callStart (Lokhttp3/Call;)V

	public static final field NONE Lokhttp3/EventListener;
	public fun <init> ()V
	public fun cacheConditionalHit (Lokhttp3/Call;Lokhttp3/Response;)V
	public fun cacheHit (Lokhttp3/Call;Lokhttp3/Response;)V
	public fun cacheMiss (Lokhttp3/Call;)V
	public fun callEnd (Lokhttp3/Call;)V
	public fun callFailed (Lokhttp3/Call;Ljava/io/IOException;)V
	public fun callStart (Lokhttp3/Call;)V

  private inner class RealCacheRequest(
    private val editor: DiskLruCache.Editor,
  ) : CacheRequest {
    private val cacheOut: Sink = editor.newSink(ENTRY_BODY)
    private val body: Sink
    var done = false

    init {
      this.body =
        object : ForwardingSink(cacheOut) {
          @Throws(IOException::class)
          override fun close() {
            synchronized(this@Cache) {

import okhttp3.MediaType.Companion.toMediaType
import okhttp3.MediaType.Companion.toMediaTypeOrNull
import okhttp3.RequestBody.Companion.toRequestBody
import okhttp3.internal.addHeaderLenient
import okhttp3.internal.cacheGet
import okhttp3.internal.platform.Platform.Companion.get
import okhttp3.java.net.cookiejar.JavaNetCookieJar
import okhttp3.testing.PlatformRule
import okio.Buffer
import okio.BufferedSink
import okio.FileSystem

    `--upgrade` seçeneği, paketler zaten yüklüyse `pip`'e onları yükseltmesini söyler.

    Bir önceki adım (dosyayı kopyalama) **Docker cache** tarafından tespit edilebildiği için, bu adım da uygun olduğunda **Docker cache'i kullanır**.

    Bu adımda cache kullanmak, geliştirme sırasında image'ı tekrar tekrar build ederken size çok **zaman** kazandırır; her seferinde bağımlılıkları **indirip yüklemek** zorunda kalmazsınız.