save (RFilter::DeliveryAgent)

    # File lib/rfilter/delivery_agent.rb, line 140
        def save(folder, continue = false)
          log(2, "Action: save to #{folder.inspect}")
          retval = if folder =~ %{(.*[^/])/$}
                     deliver_maildir($1, @message)
                   else
                     deliver_mbox(folder, @message)
                   end
          raise DeliverySuccess, "saved to mbox #{folder.inspect}" unless continue
          retval
        end