+/*--
+flow control notes
+to ensure articles go away eventually
+separate queue for each input file
+ queue expiry
+ every period, check head of backlog queue for expiry with SMretrieve
+ if too old: discard, and check next article
+ also check every backlog article as we read it
+ flush expiry
+ after too long in SEPARATED/DROPPING ie Separated/Finishing/Dropping
+ one-off: eat queued articles from flushing and write them to defer
+ one-off: connfail all connections which have any articles from flushing
+ newly read articles from flushing go straight to defer
+ this should take care of it and get us out of this state
+to avoid filling up ram needlessly
+ input control
+ limit number of queued articles for each ipf
+ pause/resume inputfile tailing
+--*/
+