),
        body = "A",
      ),
    )
    server.enqueue(
      MockResponse.Builder()
        .clearHeaders()
        .addHeader("Donut: b")
        .code(HttpURLConnection.HTTP_NOT_MODIFIED)
        .build(),
    )
    client =
      client.newBuilder()
        .cache(cache)
        .build()

    // Store a response in the cache.