title: Symfony onKernelRequest headers->set dont received on @Route
body: <p>I have functionm <strong>onKernelRequest</strong> when i want to add some custom header(in my case <code>api=true</code>||<code>$request-&gt;headers-&gt;set('api', "true")</code>) and in all <code>Request $request</code> i can get that header but when i try it on annotation its fail:</p>
  
  <ul>
  <li><strong>onKernelRequest</strong>:</li>
  </ul>
  
  <pre><code>public function onKernelRequest(RequestEvent $event)
  {
      if (!$event-&gt;isMasterRequest()) { return; }
  
      $request = $event-&gt;getRequest();
      $request-&gt;headers-&gt;set('api', "true");
      return;
  }
  </code></pre>
  
  <ul>
  <li><strong>Route</strong></li>
  </ul>
  
  <pre><code>/* @Route(
   *     "/user/info/",
   *     name="get_user_info",
   *     methods={"GET"},
   *     condition="request.headers.get('api')"
   * )
  </code></pre>
  
  <ul>
  <li><strong>Error</strong></li>
  </ul>
  
  <pre><code>Path almost matches, but Condition "request.headers.get('api')" does not evaluate to "true"
  </code></pre>