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

        .minFresh(3, TimeUnit.SECONDS)
        .onlyIfCached()
        .noTransform()
        .immutable()
        .build()
    assertThat(cacheControl.toString()).isEqualTo(
      "no-cache, no-store, max-age=1, max-stale=2, min-fresh=3, only-if-cached, " +
        "no-transform, immutable",
    )
    assertThat(cacheControl.noCache).isTrue()
    assertThat(cacheControl.noStore).isTrue()
    assertThat(cacheControl.maxAgeSeconds).isEqualTo(1)

        if (isPrivate) append("private, ")
        if (isPublic) append("public, ")
        if (mustRevalidate) append("must-revalidate, ")
        if (maxStaleSeconds != -1) append("max-stale=").append(maxStaleSeconds).append(", ")
        if (minFreshSeconds != -1) append("min-fresh=").append(minFreshSeconds).append(", ")
        if (onlyIfCached) append("only-if-cached, ")

 *   // 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())

## Retrying Requests

Sometimes connections fail: either a pooled connection was stale and disconnected, or the webserver itself couldn’t be reached. OkHttp will retry the request with a different route if one is available.

## [Calls](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-call/)

      assertEquals(204, it.code)
    }
  }

  @Test
  fun staleConnectionNotReusedForNonIdempotentRequest() {
    // Capture the connection so that we can later make it stale.
    var connection: RealConnection? = null
    client =
      client.newBuilder()
        .addNetworkInterceptor(
          Interceptor { chain ->
            connection = chain.connection() as RealConnection

If there's a problem with the connection, OkHttp will select another route and try again. This allows OkHttp to recover when a subset of a server's addresses are unreachable. It's also useful when a pooled connection is stale or if the attempted TLS version is unsupported.