code: public void setRelated(Related related) {
  		replace(RELATED, (related == null) ? null : related.getValue());
  	}
docs: <p>
  Sets the RELATED parameter value.
  </p>
  <p>
  This parameter is used by the {@link Trigger} property. It defines the
  date-time field that the property's duration (if specified) is relative
  to (for example, the start date or the end date).
  </p>
  @param related the related field or null to remove
  @see <a href="http://tools.ietf.org/html/rfc5545#page-24">RFC 5545
  p.24</a>