This library has been refactored into: https://github.com/mailgun/oxy and is being deprecated
OXY is compatible with HTTP standard library, provides the same features as Vulcan and is simpler to use. Please consider using it instead.
Vulcan library will stay there for a while in case if you are using it, but I would suggest consider migrating. Vulcand project is currently migrating to oxy library.