Suppos I have a existing file (“export.xls”) on “wwwroot/files” folder and I want to download it,
I tried to use MemoryStream like:

await ms.WriteAsync(resFile.Content);
var res = new FileStreamResult(ms, “text/csv;charset=utf-8”) { FileDownloadName = “export.xls” };
return res;
but it doesn’t work.