private IEnumerable<IndexRange> GetPageRanges()
{
pageBlob.FetchAttributes(new AccessCondition(), blobRequestOptions);
IEnumerable<PageRange> pageRanges = pageBlob.GetPageRanges(null, null, new AccessCondition(), blobRequestOptions);
pageRanges = pageRanges.OrderBy(range => range.StartOffset);
return pageRanges.Select(pr => new IndexRange(pr.StartOffset, pr.EndOffset));
}