module Concurrent::Synchronization::MriAttrVolatile::ClassMethods

def attr_volatile(*names)
  names.each do |name|
    ivar = :"@volatile_#{name}"
    class_eval <<-RUBY, __FILE__, __LINE__ + 1
      def #{name}
        #{ivar}
      end
      def #{name}=(value)
        #{ivar} = value
      end
    RUBY
  end
  names.map { |n| [n, :"#{n}="] }.flatten
end