private void AddToTree(IntervalTree <DateTimeRange> tree, List <DateTimeRange> list)
 {
     foreach (DateTimeRange s in list)
     {
         tree.Insert(s, s);
     }
 }
 public void Init()
 {
     baseDate = DateUtil.ParseDateToUtc("2007-06-30T05:16:11.000Z");
     tree     = new IntervalTree <DateTimeRange>();
 }