Does Nginx have separate queuing mechanism for requests?

[amehzenin]

Hello.

Consider the following situation: you are deploying application that can
serve 1 req./sec. What would happen if I send 10 request in 1 second? I
wrote simple app to test that:
https://github.com/amezhenin/nginx_slow_upstream . 
This test shows that your requests will be served  _in_exact_same_order_
they were sent.

For now, this looks like Nginx have some kind of queue for requests, but my
colleague(administrator) sayd that there is no any queues in Nginx. So I
wrote another question about epoll here:
http://stackoverflow.com/questions/19114001/does-epoll-preserve-the-order-in-which-fds-was-registered
. From that discussion I figured that epoll does preserves the order of
requests.

I have two questions:
1) Is there any mistakes in reasoning/code above?
2) Does Nginx have some sort of queue for requests on top of epoll? Or Nginx
uses pure epoll functionality?

Thank you, and sorry for my English :)

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,243372,243372#msg-243372