title: Envoy proxy / Move active websocket connection to another upstream host
body: <p>I'm new user of envoy proxy, maybe someone can help me</p>
  <p>I have 2 upstream hosts (UH1 and UH2), and configured envoy proxy to proxy (round robin) websocket connections from a client (frontend) to them.</p>
  <p>Let's say UH1 has an active websocket connection (WC1) and UH1 becomes down (closes all its connections) I would like to keep the connection WC1 alive with a client and move the connection to UH2. Could anyone say if it is possible?</p>
  <p>Thank you in advance!</p>