public static async Task _SendFileContents(this HttpResponse h, FileBase file, long offset, long?count, string contentsType = Consts.MimeTypes.OctetStream, CancellationToken cancel = default) { CheckStreamRange(offset, count, file.Size); using (FileStream srcStream = file.GetStream(false)) { if (offset > 0) { srcStream.Seek(offset, SeekOrigin.Begin); } await h._SendStreamContents(srcStream, count, contentsType, cancel); } }