About Symfony Request Stack I've read below page multiple time . and also I haven't found another blog post or some thing on web world introduce this Symfony class. "http://symfony.com/blog/new-in-symfony-2-4-the-request-stack"
at the page I mentioned you see a word "sub-request", what do they mean by this word? what do the mean by "more than one request in a single PHP process"?? does it mean a single PHP process which has Symfony Objects in it will handle future request ??