(ws) ws echo_server gains a new option (-p) to disable responding to pings with pongs

ws/ws_echo_server.cpp

@@ -16,7 +16,8 @@ namespace ix
                             const std::string& hostname,
                             const ix::SocketTLSOptions& tlsOptions,
                             bool ipv6,
-                            bool disablePerMessageDeflate)
+                            bool disablePerMessageDeflate,
+                            bool disablePong)
     {
         spdlog::info("Listening on {}:{}", hostname, port);
 
@@ -35,6 +36,12 @@ namespace ix
             server.disablePerMessageDeflate();
         }
 
+        if (disablePong)
+        {
+            spdlog::info("Disable responding to PING messages with PONG");
+            server.disablePong();
+        }
+
         server.setOnConnectionCallback(
             [greetings](std::shared_ptr<ix::WebSocket> webSocket,
                         std::shared_ptr<ConnectionState> connectionState) {