What is the purpose of the API toolkit in Ruby / Rails?

Question

Based on: http://api.rubyonrails.org/classes/ActiveSupport/Notifications.html

It says:

Notifications provide a toolkit API for Ruby. To perform an action in Ruby, you just need to do:

What is a toolkit API and what does it do?

Thanks!

Answer 1

Railscast is very nice in this thread:

http://railscasts.com/episodes/249-notifications-in-rails-3