* limitations under the License.
 */
@file:JvmName("HttpHeaders")

package okhttp3.internal.http

import java.io.EOFException
import java.net.HttpURLConnection.HTTP_NOT_MODIFIED
import java.net.HttpURLConnection.HTTP_NO_CONTENT
import java.util.Collections
import okhttp3.Challenge
import okhttp3.Cookie
import okhttp3.CookieJar
import okhttp3.Headers
import okhttp3.HttpUrl

          ?: throw ProtocolException(
            "Unexpected status line: $statusLine",
          )

      // Parse an optional response message like "OK" or "Not Modified". If it
      // exists, it is separated from the response code by a space.
      var message = ""
      if (statusLine.length > codeStart + 3) {
        if (statusLine[codeStart + 3] != ' ') {

As recommended by the HTTP RFC the max age of a document is defaulted to 10% of the 
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

        headers =
          headersOf(
            "Last-Modified",
            formatDate(-1, TimeUnit.HOURS)!!,
            "Expires",
            formatDate(1, TimeUnit.HOURS)!!,
          ),
        body = "ABC.1",
      ),
    )
    server.enqueue(
      MockResponse(
        headers =
          headersOf(
            "Last-Modified",
            formatDate(-1, TimeUnit.HOURS)!!,

        MockResponse.Builder()
          .addHeader("Last-Modified: $lastModifiedDate")
          .addHeader("Date: " + formatDate(-15, TimeUnit.SECONDS))
          .build(),
      )
    assertThat(conditionalRequest.headers["If-Modified-Since"])
      .isEqualTo(lastModifiedDate)
  }

  @Test
  fun defaultExpirationDateFullyCachedForMoreThan24Hours() {
    //      last modified: 105 days ago
    //             served:   5 days ago

        .clearHeaders()
        .code(HttpURLConnection.HTTP_NOT_MODIFIED)
        .addHeader("Content-Encoding: gzip")
        .build(),
    )
    server.enqueue(
      MockResponse(body = "b"),
    )
    val response1 = getResponse(newRequest("/"))
    assertThat(response1.code).isEqualTo(HttpURLConnection.HTTP_NOT_MODIFIED)
    assertContent("", response1)

 *  limitations under the License.
 */
package okhttp3.internal.cache

import java.io.IOException
import java.net.HttpURLConnection.HTTP_GATEWAY_TIMEOUT
import java.net.HttpURLConnection.HTTP_NOT_MODIFIED
import java.util.concurrent.TimeUnit.MILLISECONDS
import okhttp3.Cache
import okhttp3.EventListener
import okhttp3.Headers
import okhttp3.Interceptor
import okhttp3.Protocol
import okhttp3.Request

          conditionValue = etag
        }

        lastModified != null -> {
          conditionName = "If-Modified-Since"
          conditionValue = lastModifiedString
        }

        servedDate != null -> {
          conditionName = "If-Modified-Since"
          conditionValue = servedDateString
        }

Some requests will have a cached response. When this cached response isn’t fresh, OkHttp can do a _conditional GET_ to download an updated response if it’s newer than what’s cached. This requires headers like `If-Modified-Since` and `If-None-Match` to be added.

## Rewriting Responses

    /**
     * Creates a new event source and immediately returns it. Creating an event source initiates an
     * asynchronous process to connect the socket. Once that succeeds or fails, `listener` will be
     * notified. The caller must cancel the returned event source when it is no longer in use.
     */
    fun newEventSource(
      request: Request,
      listener: EventSourceListener,
    ): EventSource
  }