by default, we close the connection since we're hijacking,

and we don't want to manage the connections at the moment.
if so, we might want to go with regular body response via each:
http://rack.rubyforge.org/doc/SPEC.html
see: Response (after headers)
so i think we could use threads for hijacking

ref: https://github.com/macournoyer/thin/issues/157
so it seems that it would produce weird result with threads

e.g. getting different images for the same url. it's not really
thread safe after all?

Revert "so i think we could use threads for hijacking"

This reverts commit 0664a29ee75cd606e49fa555c04d1120f271ee36.
extract replay
prepare releasing 0.7.1