private MappedResultInfo GetLastByEtag(List<MappedResultInfo> reduceKeyAndEtags)
{
// the last item is either the first or the last
var first = reduceKeyAndEtags.First();
var last = reduceKeyAndEtags.Last();
if (new ComparableByteArray(first.Etag.ToByteArray()).CompareTo(new ComparableByteArray(last.Etag.ToByteArray())) < 0)
return last;
return first;
}