fanout.rb in activesupport-8.0.0.rc1

- old
+ new

@@ -1,8 +1,7 @@
 # frozen_string_literal: true
 
 require "concurrent/map"
-require "set"
 require "active_support/core_ext/object/try"
 
 module ActiveSupport
   module Notifications
     class InstrumentationSubscriberError < RuntimeError