docs: private CitrusWebSocketHandler getWebSocketClientHandler(String url) {
          CitrusWebSocketHandler handler = new CitrusWebSocketHandler();
  
          if (webSocketHttpHeaders == null) {
              webSocketHttpHeaders = new WebSocketHttpHeaders();
              webSocketHttpHeaders.setSecWebSocketExtensions(Collections.singletonList(new StandardToWebSocketExtensionAdapter(new JsrExtension(new PerMessageDeflateExtension().getName()))));
          }
  
          ListenableFuture<WebSocketSession> future = client.doHandshake(handler, webSocketHttpHeaders, UriComponentsBuilder.fromUriString(url).buildAndExpand().encode().toUri());
          try {
              future.get();
          } catch (Exception e) {
              String errMsg = String.format("Failed to connect to Web Socket server - '%s'", url);
              LOG.error(errMsg);
              throw new CitrusRuntimeException(errMsg);
          }
          return handler;
      }