*
   * @param <V1> the type returned by the first future
   * @param <V2> the type returned by the second future
   * @param <V3> the type returned by the third future
   * @param <V4> the type returned by the fourth future
   */
  public static final class Combiner4<
          V1 extends @Nullable Object,
          V2 extends @Nullable Object,
          V3 extends @Nullable Object,
          V4 extends @Nullable Object>

      )
    // Fail auth three times...
    server.enqueue(pleaseAuthenticate)
    server.enqueue(pleaseAuthenticate)
    server.enqueue(pleaseAuthenticate)
    // ...then succeed the fourth time.
    server.enqueue(
      MockResponse(body = "Successful auth!"),
    )
    java.net.Authenticator.setDefault(RecordingAuthenticator())
    client =
      client
        .newBuilder()

        .url(url)
        .query("bar".toRequestBody())
        .build()
    val response3 = client.newCall(request3).execute()
    assertThat(response3.body.string()).isEqualTo("DEFa")

    // Fourth QUERY request with body "foo" again, should be cached and return "ABC"
    val response1a = client.newCall(request1).execute()
    assertThat(response1a.body.string()).isEqualTo("ABC")

watch out of his pocket, and was looking at it uneasily, shaking
it every now and then, and holding it to his ear.

  Alice considered a little, and then said `The fourth.'

  `Two days wrong!' sighed the Hatter.  `I told you butter
wouldn't suit the works!' he added looking angrily at the March
Hare.

  `It was the BEST butter,' the March Hare meekly replied.

watch out of his pocket, and was looking at it uneasily, shaking
it every now and then, and holding it to his ear.

  Alice considered a little, and then said `The fourth.'

  `Two days wrong!' sighed the Hatter.  `I told you butter
wouldn't suit the works!' he added looking angrily at the March
Hare.

  `It was the BEST butter,' the March Hare meekly replied.