assertThat((response1.receivedResponseAtMillis - t0).toDouble()).isCloseTo(0.0, 250.0)

    // 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")

</p>

<pre>
t.z          // t.z
t.y          // t.T1.y
t.x          // (*t.T0).x

p.z          // (*p).z
p.y          // (*p).T1.y
p.x          // (*(*p).T0).x

q.x          // (*(*q).T0).x        (*q).x is a valid field selector

p.M0()       // ((*p).T0).M0()      M0 expects *T0 receiver
p.M1()       // ((*p).T1).M1()      M1 expects T1 receiver