.build()
    val call = client.newCall(request)
    call.enqueue(callback)
    val recordedResponse = callback.await(server.url("/"))
    assertThat(recordedResponse.failure, "canceled due to java.lang.RuntimeException: boom!")
    recordedResponse.failure!!.assertSuppressed { throwables: List<Throwable>? ->
      assertThat(throwables!!).contains(boom)
      Unit
    }
    assertThat(call.isCanceled()).isTrue()