Creating an Excel file on the fly and have it download/save on the client

Question: What is an alternative to the last three lines of the following code in ASP.NET Core 1.1 and/or what are workarounds? On these last three lines VS2015 is complaining HttpResponse does not contain a definition for OutputStream, Flush(), End()

Background: In my ASP.NET Core 1.1 app I'm using EPPlus.Core to export data on the fly to Excel and have it downloaded/save on the client side. As a starter, I'm trying to mimic the following example (taken from here), but VS2015 is not recognizing the last 3 lines of this code.

public void ExportListUsingEPPlus()
{
    var data = new[]{
                        new{ Name="Ram", Email="ram@techbrij.com", Phone="111-222-3333" },
                        new{ Name="Shyam", Email="shyam@techbrij.com", Phone="159-222-1596" },
                        new{ Name="Mohan", Email="mohan@techbrij.com", Phone="456-222-4569" },
                        new{ Name="Sohan", Email="sohan@techbrij.com", Phone="789-456-3333" },
                        new{ Name="Karan", Email="karan@techbrij.com", Phone="111-222-1234" },
                        new{ Name="Brij", Email="brij@techbrij.com", Phone="111-222-3333" }
                };

    ExcelPackage excel = new ExcelPackage();
    var workSheet = excel.Workbook.Worksheets.Add("Sheet1");
    workSheet.Cells[1, 1].LoadFromCollection(data, true);
    using (var memoryStream = new MemoryStream())
    {
        Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
        Response.Headers.Add("content-disposition", "attachment;  filename=Contact.xlsx");
        excel.SaveAs(memoryStream);
        memoryStream.WriteTo(Response.OutputStream);
        Response.Flush();
        Response.End();
    }
}