Returning value from subsystem with DispatchQueue.sync - Swift 3.0 - October 4 2016

gistfile1.txt

        // pretending this is a subsystem
        let holdval = HoldAValue()
        
        var avalue: Int {
            var i: Int = 0
            DispatchQueue.global(qos: .userInitiated).sync {
                  i = holdval.anIntValue
            }
            return i
        }
        

        
        print ("\(avalue) avalue")