frankenphp-symfony: tiny refactoring (#151)

Tiny refactoring as suggested in
php-runtime/runtime#148 (comment)

Author: dunglas

src/Runner.php

@@ -22,25 +22,24 @@ public function __construct(private HttpKernelInterface $kernel)
 
     public function run(): int
     {
-        $kernel = $this->kernel;
         $server = array_filter($_SERVER, static fn (string $key) => !str_starts_with($key, 'HTTP_'), ARRAY_FILTER_USE_KEY);
         $server['APP_RUNTIME_MODE'] = 'web=1&worker=1';
 
-        $handler = static function () use ($kernel, $server, &$sfRequest, &$sfResponse): void {
+        $handler = function () use ($server, &$sfRequest, &$sfResponse): void {
             // Merge the environment variables coming from DotEnv with the ones tied to the current request
             $_SERVER += $server;
 
             $sfRequest = Request::createFromGlobals();
-            $sfResponse = $kernel->handle($sfRequest);
+            $sfResponse = $this->kernel->handle($sfRequest);
 
             $sfResponse->send();
         };
 
         do {
             $ret = \frankenphp_handle_request($handler);
 
-            if ($kernel instanceof TerminableInterface && $sfRequest && $sfResponse) {
-                $kernel->terminate($sfRequest, $sfResponse);
+            if ($this->kernel instanceof TerminableInterface && $sfRequest && $sfResponse) {
+                $this->kernel->terminate($sfRequest, $sfResponse);
             }
 
             gc_collect_cycles();