@Test void redirectedHeaderUsesOriginalHostAndPort() throws Exception {
    Request forwarded = new Request.Builder()
      .url(url(server, "/"))
      .addHeader("Host", "zipkin.com")
      .addHeader("X-Forwarded-Proto", "https")
      .addHeader("X-Forwarded-Port", "444")
      .build();

    Response response = client.newBuilder().followRedirects(false).build()
      .newCall(forwarded).execute();

    // Redirect header should be the proxy, not the backed IP/port
    assertThat(response.header("Location"))
      .isEqualTo("/zipkin/");
  }
Simulate a proxy which forwards / to zipkin as opposed to resolving / -> /zipkin first
zipkin-server/src/test/java/zipkin2/server/internal/ITZipkinServer.java