.newBuilder()
        .addHeader("Response-Interceptor", "Cupcake") // 3. Added third.
        .build()
    }
    val request =
      Request
        .Builder()
        .url(server.url("/"))
        .build()
    val response = client.newCall(request).execute()
    assertThat(response.headers("Response-Interceptor"))
      .containsExactly("Cupcake", "Donut")
    val recordedRequest = server.takeRequest()