This tool is no longer maintained. New version is implemented in Node.js and available at https://github.com/biesiad/deelay.
Inline delay proxy for http resources
Slow loading resources (images, scripts, etc) can break your code. Test it simulating unexpected network conditions applied to specific resource.
$ gem install deelay
$ deelay
== Sinatra/1.3.3 has taken the stage on 4567 for development with backup from Thin
Thin web server (v1.4.1 codename Chromeo)
Maximum connections set to 1024
Listening on 0.0.0.0:4567, CTRL+C to stop
curl localhost:4567/1000/http://mysite.com/image.gif
bundle exec rake test