title: RRULE for the weekend including the first sunday of a month
body: <p>We have a event every year on the <em>weekend (Fr-Su) that includes the first Sunday of June</em>. How would I create a <em>iCalendar Event</em> that expresses these three days (whole day events)?</p>
  <p>Creating a rule for the first Sunday is easy. But for the Saturday and Friday, I did not succeed to create a rule that counts backwards (<a href="https://www.rfc-editor.org/rfc/rfc5545#section-3.3.10" rel="nofollow noreferrer">RFC 5545</a> says <code>INTERVAL</code>, <code>COUNT</code> must be positive]. Moreover I could not think of a different expression that would start from the Friday - it could be the last Friday of May, but also the first in June.</p>