Return immediately if request is not json

Fetching the contents before this check may result in OutOfMemory excpetion if the request is multipart with files.

src/Qandidate/Common/Symfony/HttpKernel/EventListener/JsonRequestTransformerListener.php

@@ -27,13 +27,13 @@ public function onKernelRequest(GetResponseEvent $event)
     {
         $request = $event->getRequest();
 
-        $content = $request->getContent();
-
-        if (empty($content)) {
+        if (! $this->isJsonRequest($request)) {
             return;
         }
+
+        $content = $request->getContent();
 
-        if (! $this->isJsonRequest($request)) {
+        if (empty($content)) {
             return;
         }