extended

# File activesupport/lib/active_support/per_thread_registry.rb, line 42
    def self.extended(object)
      ActiveSupport::Deprecation.warn(<<~MSG)
        ActiveSupport::PerThreadRegistry is deprecated and will be removed in Rails 7.1.
        Use `Module#thread_mattr_accessor` instead.
      MSG
      object.instance_variable_set :@per_thread_registry_key, object.name.freeze
    end