ype invoked in Envoy.</p><ul><li>HTTP proxy listener: This happens when the port of the external service is same
as one of the service ports defined in the cluster.
In this scenario, when the BlackHoleCluster is hit,
<code>istio_requests_total</code> will get increased like this:</li></ul><pre><code class=language-json data-expandlinks=true data-repo=istio>{
  &#34;metric&#34;: {
    &#34;__name__&#34;: &#34;istio_requests_total&#34;,
    &#34;connection_security_policy&#34;: &#34;unknown&#34;,
    &#34;des