/** The HTTP {@code Access-Control-Expose-Headers} header field name. */
  public static final String ACCESS_CONTROL_EXPOSE_HEADERS = "Access-Control-Expose-Headers";
  /** The HTTP {@code Access-Control-Max-Age} header field name. */
  public static final String ACCESS_CONTROL_MAX_AGE = "Access-Control-Max-Age";
  /** The HTTP {@code Age} header field name. */

### Install Control plane

This can run in any cluster. A mesh should have at least one cluster should run Pilot or equivalent XDS server,
and it is recommended to have Pilot running in each region and in multiple availability zones for multi cluster.

```bash
iop istio-control istio-discovery $IBASE/istio-control/istio-discovery \
            --set global.istioNamespace=istio-system

	cp manifests/charts/istio-control/istio-discovery/files/injection-template.yaml manifests/charts/istiod-remote/files
	cp manifests/charts/istio-control/istio-discovery/files/gateway-injection-template.yaml manifests/charts/istiod-remote/files
	cp manifests/charts/istio-control/istio-discovery/templates/istiod-injector-configmap.yaml manifests/charts/istiod-remote/templates

    val headers = headersOf("Cache-Control", "max-age=12", "Pragma", "must-revalidate", "Pragma", "public")
    val cacheControl = parse(headers)
    assertThat(cacheControl.toString()).isEqualTo("max-age=12, public, must-revalidate")
  }

  @Test
  fun parseCacheControlHeaderValueIsRetained() {
    val value = "max-age=12"
    val headers = headersOf("Cache-Control", value)
    val cacheControl = parse(headers)

    val headers =
      Headers.headersOf(
        "cache-control",
        "no-store",
        "Cache-Control",
        "no-cache",
      )
    val headerMap = headers.toMultimap()
    assertThat(headerMap["cache-control"]!!.size).isEqualTo(2)
    assertThat(headerMap["Cache-Control"]!!.size).isEqualTo(2)
  }

        httpResponse.addHeader(ACCESS_CONTROL_ALLOW_ORIGIN, origin);
        httpResponse.addHeader(ACCESS_CONTROL_ALLOW_METHODS, fessConfig.getApiCorsAllowMethods());
        httpResponse.addHeader(ACCESS_CONTROL_ALLOW_HEADERS, fessConfig.getApiCorsAllowHeaders());
        httpResponse.addHeader(ACCESS_CONTROL_MAX_AGE, fessConfig.getApiCorsMaxAge());
        httpResponse.addHeader(ACCESS_CONTROL_ALLOW_CREDENTIALS, fessConfig.getApiCorsAllowCredentials());

    assertTrue(foo1.equals(foo1));
    assertEquals(control("foo", 1), foo1);
    assertEquals(control("bar", 2), entry("bar", 2));
    assertFalse(control("foo", 1).equals(entry("foo", 2)));
    assertFalse(foo1.equals(control("bar", 1)));
    assertFalse(foo1.equals(new Object()));
    assertFalse(foo1.equals(null));
  }

  public void testEqualsNull() {
    assertEquals(control(NK, 1), entry(NK, 1));

kube-system        coredns-5dd5756b68-mgjn9                             10.244.0.2  ambient-control-plane None                                TCP
kube-system        coredns-5dd5756b68-nzlpw                             10.244.0.3  ambient-control-plane None                                TCP
local-path-storage local-path-provisioner-6f8956fb48-vvnpn              10.244.0.4  ambient-control-plane None                                TCP

  }

  companion object {
    /**
     * Cache control request directives that require network validation of responses. Note that such
     * requests may be assisted by the cache via conditional GET requests.
     */
    @JvmField
    val FORCE_NETWORK = commonForceNetwork()

    /**
     * Cache control request directives that uses the cache only, even if the cached response is

    open fun headers(headers: Headers) = commonHeaders(headers)

    /**
     * Sets this request's `Cache-Control` header, replacing any cache control headers already
     * present. If [cacheControl] doesn't define any directives, this clears this request's
     * cache-control headers.
     */
    open fun cacheControl(cacheControl: CacheControl): Builder = commonCacheControl(cacheControl)