As per the article (link given below ) cant a asyncRFC have an CHANGING parameter .Is that the only way whether an RFC call in syn or async ?
https://help.sap.com/saphelp_nw73ehp1/helpdata/en/48/89673284b84e6fe10000000a421937/frameset.htm
And what are the ways we can differentiate between sRFC and AsyncRFC ?