title: Get route path '/blog/{slug}' of current request in Symfony
body: <p>For some logging/monitoring i would like to get the current route path including placeholders.</p>
  <p>If my route is /blog/{slug} and the request is to http://localhost/blog/foobar what i need is &quot;/blog/{slug}&quot;</p>
  <p>In request listeners this value seem to not be inside the request object. I only find the resolved path which i am not interested in.</p>
  <p>In Compiler passes I have the issue that any Router related service I try to get from the ContainerBuilder returns an exception. If i had the</p>
  <p>What is a clean way to obtain this?</p>