Strange SPDY behaviour about request time with stastic proxy cached content.

[endo]

Sorry, forgot link image for visualizing a problem: 
http://i59.fastpic.ru/big/2013/0830/87/689d2b6f84dfb88fe5a57b7ad60def87.png

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,242350,242351#msg-242351