val headers =
      Headers.Builder()
        .add(
          "WWW-Authenticate",
          "Digest realm=\"myrealm\", nonce=\"fjalskdflwejrlaskdfjlaskdjflaks" +
            "jdflkasdf\", qop=\"auth\", stale=\"FALSE\"",
        )
        .build()
    val challenges = headers.parseChallenges("WWW-Authenticate")
    assertThat(challenges.size).isEqualTo(1)
    assertThat(challenges[0].scheme).isEqualTo("Digest")

_2020-04-06_

**This release fixes a severe bug where OkHttp incorrectly detected and recovered from unhealthy
connections.** Stale or canceled connections were incorrectly attempted when they shouldn't have
been, leading to rare cases of infinite retries. Please upgrade to this release!

 *  Fix: don't return stale DNS entries in `DnsOverHttps`. We were caching DNS results indefinitely

 *   // The resource was cached! Show it.
 * } else {
 *   // The resource was not cached.
 * }
 * ```
 *
 * This technique works even better in situations where a stale response is better than no response.
 * To permit stale cached responses, use the `max-stale` directive with the maximum staleness in
 * seconds:
 *
 * ```java
 * Request request = new Request.Builder()
 *     .cacheControl(new CacheControl.Builder()

      this.maxAgeSeconds = maxAgeSecondsLong.commonClampToInt()
    }

    /**
     * Accept cached responses that have exceeded their freshness lifetime by up to `maxStale`. If
     * unspecified, stale cache responses will not be used.
     *
     * @param maxStale a non-negative integer. This is stored and transmitted with
     *     [TimeUnit.SECONDS] precision; finer precision will be lost.
     */
    fun maxStale(

  // TODO GET preferred order - with tests to confirm this
  // 1. successful fresh cached GET response
  // 2. unsuccessful (404, 500) fresh cached GET response
  // 3. successful network response
  // 4. successful stale cached GET response
  // 5. unsuccessful response
  @Test
  fun usesCache() {
    val cache = Cache(cacheFs, "cache".toPath(), (100 * 1024).toLong())

 * both.
 *
 * Selecting a cache strategy may add conditions to the request (like the "If-Modified-Since" header
 * for conditional GETs) or warnings to the cached response (if the cached data is potentially
 * stale).
 */
class CacheStrategy internal constructor(
  /** The request to send on the network, or null if this call doesn't use the network. */
  val networkRequest: Request?,

  private var mostRecentRebuildFailed: Boolean = false

  /**
   * To differentiate between old and current snapshots, each entry is given a sequence number each
   * time an edit is committed. A snapshot is stale if its sequence number is not equal to its
   * entry's sequence number.
   */
  private var nextSequenceNumber: Long = 0

  private val cleanupQueue = taskRunner.newQueue()
  private val cleanupTask =

  private fun getCacheOnlyResponse(request: Request): Response? {
    if (client.cache != null) {
      try {
        // Use the cache without hitting the network first
        // 504 code indicates that the Cache is stale
        val onlyIfCached =
          CacheControl.Builder()
            .onlyIfCached()
            .build()

        var cacheUrl = request.url

        val cacheRequest =

          },
        )
        .build()
    dns["san.com"] = Dns.SYSTEM.lookup(server.hostName).subList(0, 1)
    assert200Http2Response(execute(url), server.hostName)

    // Simulate a stale connection in the pool.
    connection.get()!!.socket().close()
    val sanUrl = url.newBuilder().host("san.com").build()
    assert200Http2Response(execute(sanUrl), "san.com")