* attempts to the current point use this function.
 *
 * ```java
 * private int responseCount(Response response) {
 *   int result = 1;
 *   while ((response = response.priorResponse()) != null) {
 *     result++;
 *   }
 *   return result;
 * }
 * ```
 *
 * [1]: https://tools.ietf.org/html/rfc2817
 */
fun interface Authenticator {
  /**

    val sanUrl =
      url
        .newBuilder()
        .host("san.com")
        .build()
    execute(sanUrl).use { response ->
      assertThat(response.code).isEqualTo(200)
      assertThat(response.priorResponse!!.code).isEqualTo(421)
      assertThat(response.body.string()).isEqualTo("after misdirect")
    }
    val c0e0 = server.takeRequest()
    assertThat(c0e0.connectionIndex).isEqualTo(0)

    }
    ```

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

    ```kotlin
    val Response.responseCount: Int
      get() = generateSequence(this) { it.priorResponse }.count()
    ```
=== ":material-language-java: Java"
    ```java
      private final OkHttpClient client;

      public Authenticate() {
        client = new OkHttpClient.Builder()

    type declaration was nullable to support rare cases like the body on `Response.cacheResponse`,
    `Response.networkResponse`, and `Response.priorResponse`. In such cases the body is now
    non-null, but attempts to read its content will fail.
 *  New: Kotlin-specific APIs for request tags. Kotlin language users can lookup tags with a type

    val challengeResponse = authenticator.responses[0]
    assertThat(
      challengeResponse.request.url
        .toUrl()
        .path,
    ).isEqualTo("/b")
    val redirectedBy = challengeResponse.priorResponse
    assertThat(
      redirectedBy!!
        .request.url
        .toUrl()
        .path,
    ).isEqualTo("/a")
  }

  @Test
  fun attemptAuthorization20Times() {