Hi there. I want to notice that after updating rack version from 1.4.1 
to 1.4.3 the simple implementation of SSE stoped working for me(see 
application example in the attachment).<br>Gem list when that example works:<br><br>bundler (1.2.2)<br>daemons (1.1.8)<br>eventmachine (0.12.10)<br>haml (3.1.7)<br>rack (1.4.1)<br>rack-protection (1.2.0)<br>rake (10.0.2)<br>rubygems-bundler (1.1.0)<br>rvm (1.11.3.5)<br>sinatra (1.3.3)<br>thin (1.5.0)<br>tilt (1.3.3)<br><br>Gem list when that example doesn't work:<br>bundler (1.2.2)<br>daemons (1.1.8)<br>eventmachine (0.12.10)<br>haml (3.1.7)<br>rack (1.4.3)<br>rack-protection (1.2.0)<br>rake (10.0.2)<br>rubygems-bundler (1.1.0)<br>rvm (1.11.3.5)<br>sinatra (1.3.3)<br>thin (1.5.0)<br>tilt (1.3.3)<br><br>My environment:<br>&nbsp;- Ruby version is ruby 1.9.3p327 (2012-11-10 revision 37606) [x86_64-linux]<br>&nbsp;- Ubuntu 12.04 (precise) 64-bit, Linux 3.2.0-35-generic, GNOME 3.4.2<br>&nbsp;- Firefox 18.0<br>What
 do I mean by SSE doesn't work? - It tries to reconnect forever(with 
delay of a few seconds which is default for EventSource implementation -
 see http://www.w3.org/TR/eventsource/#the-eventsource-interface for me 
info, reconnection time option). You may see these reconnection retries 
in server logs or by opening "Network" tab in firebug<br>