Swift 函数做参数和闭包做参数的一个细节差别

func demo(str:String,addPrefix:(String)->String)->String{
        return addPrefix(str)
    }
    func addPrefix(str2:String)->String{
        return "prefix"+str2
    }

print(demo("123123", addPrefix: addPrefix))

func processWithBlock(cmdStr:String?,blockProperty:(backMsg:String) ->())->String{
        blockProperty(backMsg :"backMsg---by block inside func")
        return ""
    }