module ActiveSupport::PerThreadRegistry

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

def instance
  Thread.current[@per_thread_registry_key] ||= new
end

def method_missing(name, *args, &block)
  # Caches the method definition as a singleton method of the receiver.
  #
  # By letting #delegate handle it, we avoid an enclosure that'll capture args.
  singleton_class.delegate name, to: :instance
  send(name, *args, &block)
end