* occur after a call is canceled. Typically cancellation takes effect when an expensive I/O
   * operation is required.
   *
   * This is invoked at most once, even if [Call.cancel] is invoked multiple times. It may be
   * invoked at any point in a call's life, including before [callStart] and after [callEnd].
   */
  open fun canceled(call: Call) {
  }

  /**
   * Invoked when a call fails due to cache rules.

   180E; MONGOLIAN VOWEL SEPARATOR
   200C; ZERO WIDTH NON-JOINER
   200D; ZERO WIDTH JOINER
   2028; LINE SEPARATOR
   2029; PARAGRAPH SEPARATOR
   2060; WORD JOINER
   2061; FUNCTION APPLICATION
   2062; INVISIBLE TIMES
   2063; INVISIBLE SEPARATOR
   206A-206F; [CONTROL CHARACTERS]
   FEFF; ZERO WIDTH NO-BREAK SPACE
   FFF9-FFFC; [CONTROL CHARACTERS]

     }
    ```

    You may also skip the retry when you’ve hit an application-defined attempt limit:

    ```kotlin
    if (response.responseCount >= 3) {
      return null // If we've failed 3 times, give up.
    }
    ```

    This above code relies on this `responseCount` extension val:

    ```kotlin
    val Response.responseCount: Int

      private val useCompression: Boolean = true,
      private val out: Buffer,
    ) {
      /**
       * In the scenario where the dynamic table size changes multiple times between transmission of
       * header blocks, we need to keep track of the smallest value in that interval.
       */
      private var smallestHeaderTableSizeSetting = Integer.MAX_VALUE

    assertThat(peer.takeFrame().type).isEqualTo(Http2.TYPE_HEADERS)
    assertThat(peer.takeFrame().type).isEqualTo(Http2.TYPE_RST_STREAM)
  }

  /**
   * Confirm that the client times out if the server stalls after 3 bytes. After the timeout the
   * connection is still considered healthy while we await the degraded pong. When that doesn't
   * arrive the connection goes unhealthy.
   */

// help : 2014-06-26 Innovation service Limited
help

// helsinki : 2015-02-05 City of Helsinki
helsinki

// here : 2014-02-06 Charleston Road Registry Inc.
here

// hermes : 2014-07-10 HERMES INTERNATIONAL
hermes

// hgtv : 2015-07-02 Lifestyle Domain Holdings, Inc.
hgtv

// hiphop : 2014-03-06 Dot Hip Hop, LLC
hiphop

// hisamitsu : 2015-07-16 Hisamitsu Pharmaceutical Co.,Inc.

health.vn healthcare heavy.jp heguri.nara.jp heimatunduhren.museum hekinan.aichi.jp hellas.museum help helsinki helsinki.museum hembygdsforbund.museum hemne.no hemnes.no hemsedal.no hepforge.org her.jp herad.no here here-for-more.info heritage.museum hermes herokuapp.com herokussl.com heroy.more-og-romsdal.no heroy.nordland.no herøy.møre-og-romsdal.no herøy.nordland.no heteml.net hgtv hi.cn hi.us hicam.net hichiso.gifu.jp hida.gifu.jp hidaka.hokkaido.jp hidaka.kochi.jp hidaka.saitama.jp hidaka.wakayama.jp...

12475..1247F  ; disallowed                             # NA   <reserved-12475>..<reserved-1247F>
12480..12543  ; valid                                  # 8.0  CUNEIFORM SIGN AB TIMES NUN TENU..CUNEIFORM SIGN ZU5 TIMES THREE DISH TENU
12544..12F8F  ; disallowed                             # NA   <reserved-12544>..<reserved-12F8F>

    .url("https://www.nytimes.com/")
    .build();
client.newCall(newYorkTimesRequest).enqueue(new Callback() {
  ...
});
```

Running this race over home WiFi shows the Times (`0002`) completes just slightly sooner than the Post (`0001`):

```
0001 https://www.washingtonpost.com/
0001 0.000 callStart
0002 https://www.nytimes.com/
0002 0.000 callStart
0002 0.010 dnsStart

   * share the same connection without sharing the same hostname.
   */
  private var noCoalescedConnections = false

  /**
   * The number of times there was a problem establishing a stream that could be due to route
   * chosen. Guarded by this.
   */
  internal var routeFailureCount = 0

  private var successCount = 0
  private var refusedStreamCount = 0