chef

https://github.com/opscode/chef

Ruby

A systems integration framework, built to bring the benefits of configuration management to your entire infrastructure.

Chef::Resource::RemoteFile#use_conditional_get

Disable or enable ETag and Last Modified conditional GET. Equivalent to
  use_etag(true_or_false)
  use_last_modified(true_or_false)

Source | Google | Stack overflow

Edit

git clone [email protected]:opscode/chef.git
cd chef
open lib/chef/resource/remote_file.rb

Contribute

# Make a new branch
git checkout -b -your-name--update-docs-Chef--Resource--RemoteFile-use_conditional_get-for-pr

# Commit to git
git add lib/chef/resource/remote_file.rbgit commit -m "better docs for Chef::Resource::RemoteFile#use_conditional_get"

# Open pull request
gem install hub # on a mac you can `brew install hub`
hub fork
git push <your name> -your-name--update-docs-Chef--Resource--RemoteFile-use_conditional_get-for-pr
hub pull-request

# Celebrate!