DownloadManager.ColumnBytesDownloadedSoFar always returning 0

Question

Im using the following code to try and check what the download progress is and it is always returning 0. Does anyone know why this is? I cant get it to be anything but 0.

DownloadManager.Query query = new DownloadManager.Query();
query.SetFilterById(downloadID);
Android.Database.ICursor cursor = downloadManager.InvokeQuery(query);


cursor.MoveToFirst();
for (int i = 0; i < 10; i++)
{
    System.Threading.Thread.Sleep(50);

    string s = cursor.GetString(cursor.GetColumnIndex(DownloadManager.ColumnBytesDownloadedSoFar));
    Log.Debug("Total Bytes", s + " = string at position " + cursor.GetColumnIndex(DownloadManager.ColumnBytesDownloadedSoFar));
}