    # File bin/experimental-filter.rb, line 132
    def process_queue
      files = Dir[File.join($queue, 'new') + '/*'].sort { |a, b|
        queue_file_time(a) <=> queue_file_time(b)
      }
      files.each { |queue_file_name|
        begin
          File.open(queue_file_name) { |queue_file|
            RFilter::DeliveryAgent.process(queue_file, $log) { |agent|
              Deliver.new(agent).main
            }
          }
        rescue RFilter::DeliveryAgent::DeliverySuccess
          File::unlink(queue_file_name)
        rescue RFilter::DeliveryAgent::DeliveryReject
          # FIXME: for now, reject just drops the message on the floor
          File::unlink(queue_file_name)
        rescue RFilter::DeliveryAgent::DeliveryComplete
          # FIXME: truly defer somehow
        end
      }
    end