PARTSTAT
Purpose: To specify the participation status for the calendar user specified by the property in this case for the attendee. The possible values are defined in the enum PartstatJournal and PartstatTodo Use e.g. PartstatJournal.ACCEPTED.name to put a correct String value in this field. If no value (null) is passed for the Partstat, it will be interpreted as NEEDS-ACTION as according to the RFC. Other values are accepted and treated as NEEDS-ACTION. see [https://tools.ietf.org/html/rfc5545#section-3.8.4.1] and [https://tools.ietf.org/html/rfc5545#section-3.2.12] Type: String