fix ability to recursively call the respond method. Fixes beyondcode#173

Author: mpociot

src/WebSockets/Messages/PusherChannelProtocolMessage.php

@@ -31,7 +31,7 @@ public function respond()
     {
         $eventName = Str::camel(Str::after($this->payload->event, ':'));
 
-        if (method_exists($this, $eventName)) {
+        if (method_exists($this, $eventName) && $eventName !== 'respond') {
             call_user_func([$this, $eventName], $this->connection, $this->payload->data ?? new stdClass());
         }
     }