title: Does DDay Ical library calculate recurring rules correctly?
body: <p>I've run some tests. Here is my code:</p>
  
  <pre><code>var systemTimeZone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");
  var icalTimeZone = iCalTimeZone.FromSystemTimeZone(systemTimeZone);
  
  var startTimeSearch = new DateTime(2015, 9, 8, 0, 0, 0, DateTimeKind.Utc);
  var endTimeSearch = new DateTime(2015, 12, 1, 00, 0, 0, DateTimeKind.Utc);
  
  var iCalendar = new iCalendar();
  var pacificTimeZone = _iCalendar.AddTimeZone(icalTimeZone);
  
  var event = new Event
  {
      Summary = "This is an event at 2015-09-08 10:30 PST (2015-09-08 17:30 UTC)",
      DTStart = new iCalDateTime(2015, 9, 8, 10, 30, 0, pacificTimeZone.TZID, iCalendar),
      Duration = new TimeSpan(0, 1, 0, 0)
  };
  
  var rp = new RecurrencePattern("FREQ=WEEKLY;UNTIL=20151112T080000Z;WKST=SU;BYDAY=TU");
  
  event.RecurrenceRules.Add(rp);
  iCalendar.Events.Add(_event);
  var occurrences = iCalendar.GetOccurrences(startTimeSearch, endTimeSearch);
  </code></pre>
  
  <hr>
  
  <p>Here's the result:</p>
  
  <p>10 occurences - here are the occurences' Period.StartTime.Value and UTC properties</p>
  
  <p><strong>Value</strong> - 9/8/2015 10:30:00 - <strong>UTC</strong> 9/8/2015 17:30:00<br>
  <strong>Value</strong> - 9/15/2015 10:30:00 - <strong>UTC</strong> 9/15/2015 17:30:00<br>
  <strong>Value</strong> - 9/22/2015 10:30:00 - <strong>UTC</strong> 9/22/2015 17:30:00<br>
  <strong>Value</strong> - 9/29/2015 10:30:00 - <strong>UTC</strong> 9/29/2015 17:30:00<br>
  <strong>Value</strong> - 10/6/2015 10:30:00 - <strong>UTC</strong> 10/6/2015 17:30:00<br>
  <strong>Value</strong> - 10/13/2015 10:30:00 - <strong>UTC</strong> 10/13/2015 17:30:00<br>
  <strong>Value</strong> - 10/20/2015 10:30:00 - <strong>UTC</strong> 10/20/2015 17:30:00<br>
  <strong>Value</strong> - 10/27/2015 10:30:00 - <strong>UTC</strong> 10/27/2015 17:30:00<br>
  <strong>Value</strong> -11/3/2015 10:30:00 - <strong>UTC</strong> 11/3/2015 17:30:00 <strong>(THIS SHOULD BE 18:30:00!)</strong><br>
  <strong>Value</strong> - 11/10/2015 10:30:00 - <strong>UTC</strong> 11/10/2015 17:30:00 <strong>(THIS SHOULD BE 18:30:00!)</strong>  </p>
  
  <p><a href="https://i.stack.imgur.com/30jNn.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/30jNn.png" alt="enter image description here"></a></p>
  
  <p>As you can see, the last two should have a UTC time of 18:30:00. So I'm wondering if this is just the way DDay Ical works and I shouldn't count on it getting the UTC datetime right, or if I'm doing something wrong.</p>