optimize duplication of Request objects

src/Symfony/Component/HttpFoundation/Request.php

@@ -223,14 +223,34 @@ class Request
     public function duplicate(array $query = null, array $request = null, array $attributes = null, array $cookies = null, array $files = null, array $server = null)
     {
         $dup = clone $this;
-        $dup->initialize(
-            null !== $query ? $query : $this->query->all(),
-            null !== $request ? $request : $this->request->all(),
-            null !== $attributes ? $attributes : $this->attributes->all(),
-            null !== $cookies ? $cookies : $this->cookies->all(),
-            null !== $files ? $files : $this->files->all(),
-            null !== $server ? $server : $this->server->all()
-        );
+        if ($query !== null) {
+          $dup->query = new ParameterBag($query);
+        }
+        if ($request !== null) {
+          $dup->request = new ParameterBag($request);
+        }
+        if ($attributes !== null) {
+          $dup->attributes = new ParameterBag($attributes);
+        }
+        if ($cookies !== null) {
+          $dup->cookies = new ParameterBag($cookies);
+        }
+        if ($files !== null) {
+          $dup->files = new FileBag($files);
+        }
+        if ($server !== null) {
+          $dup->server = new ServerBag($server);
+          $dup->headers = new HeaderBag($dup->server->getHeaders());
+        }
+        $this->languages = null;
+        $this->charsets = null;
+        $this->acceptableContentTypes = null;
+        $this->pathInfo = null;
+        $this->requestUri = null;
+        $this->baseUrl = null;
+        $this->basePath = null;
+        $this->method = null;
+        $this->format = null;
 
         return $dup;
     }

src/Symfony/Component/HttpKernel/bootstrap.php

@@ -1243,14 +1243,34 @@ class Request
     public function duplicate(array $query = null, array $request = null, array $attributes = null, array $cookies = null, array $files = null, array $server = null)
     {
         $dup = clone $this;
-        $dup->initialize(
-            null !== $query ? $query : $this->query->all(),
-            null !== $request ? $request : $this->request->all(),
-            null !== $attributes ? $attributes : $this->attributes->all(),
-            null !== $cookies ? $cookies : $this->cookies->all(),
-            null !== $files ? $files : $this->files->all(),
-            null !== $server ? $server : $this->server->all()
-        );
+        if ($query !== null) {
+          $dup->query = new ParameterBag($query);
+        }
+        if ($request !== null) {
+          $dup->request = new ParameterBag($request);
+        }
+        if ($attributes !== null) {
+          $dup->attributes = new ParameterBag($attributes);
+        }
+        if ($cookies !== null) {
+          $dup->cookies = new ParameterBag($cookies);
+        }
+        if ($files !== null) {
+          $dup->files = new FileBag($files);
+        }
+        if ($server !== null) {
+          $dup->server = new ServerBag($server);
+          $dup->headers = new HeaderBag($dup->server->getHeaders());
+        }
+        $this->languages = null;
+        $this->charsets = null;
+        $this->acceptableContentTypes = null;
+        $this->pathInfo = null;
+        $this->requestUri = null;
+        $this->baseUrl = null;
+        $this->basePath = null;
+        $this->method = null;
+        $this->format = null;
         return $dup;
     }
     public function __clone()