(##l < QueueLength) -> (sum e: #x:makreel:interface-name events. #.name qin (e) . component_queue (l = l <| #.name events (e)))
 + (l != [] && #.name is (head (l))) -> #.name qout (#.name projection  (head (l))) . component_queue (l = tail (l))
 + (##l == QueueLength) -> (sum e: #x:makreel:interface-name events. #.name qin (e) . queue_full . delta)
