C# - Calling Response.TransmitFile() From Static Method

I have a number of pages which need to support exporting data to an Excel spreadsheet. I can generate the Excel files just fine, but I'm trying to work out how to abstract this behavior so it's easily reusable from all of the pages where I need it. My current idea is to use a static utility method, as follows:

[Code]....

The click handler where I'm calling SendExcelFile looks like this:

protected void lnkExport_Click(object sender, EventArgs e)
{
List<List<string>> dataList = GatherDataForSpreadsheet();
Utility.SendExcelFile(this, "fileNameForDownload.xlsx", dataList, "MyReports");
}

This code works just fine as an instance method of the calling page. As a static method, though, it doesn't work at all. When I click the button that invokes this, the browser shows the loading animations indefinitely, but never prompts for a file download.

EDIT: If I remove the call to File.Delete() at the end, the method works as expected. Does Response.TransmitFile() do the transfer asynchronously?

EDIT 2: I just needed to call Response.Flush() before I deleted the file.