// A conditional cache hit updates the cache.
    Thread.sleep(500) // Make sure t0 and t1 are distinct.
    val t1 = System.currentTimeMillis()
    val response2 = get(server.url("/a"))
    assertThat(response2.code).isEqualTo(HttpURLConnection.HTTP_OK)
    assertThat(response2.body.string()).isEqualTo("A")
    assertThat(response2.header("Allow")).isEqualTo("GET, HEAD")
    val updatedTimestamp = response2.receivedResponseAtMillis