public double Cal()
        {
            double res = new CommonAsyncHelper().DoCalJob();
            var    _   = new CommonAsyncHelper().DoAsyncJobDefault();

            return(res);
        }
        public double CalWithSuppressSyncContext()
        {
            double res = new CommonAsyncHelper().DoCalJob();
            var    _   = new CommonAsyncHelper().DoAsyncJobSuppressContext();

            return(res);
        }
        public double CalWithAwaitfalse()
        {
            double res = new CommonAsyncHelper().DoCalJob();
            var    _   = new CommonAsyncHelper().DoAsyncJobConfigureAwaitfalse();

            return(res);
        }
        public double CalWithTaskRun()
        {
            double res = new CommonAsyncHelper().DoCalJob();

            Task.Run(() => new CommonAsyncHelper().DoAsyncJobDefault());
            return(res);
        }