partial         void CopyExtraPropertiesToClone(SystemEvent clone, bool includeLocalProperties);
 public SystemEvent Clone(bool includeLocalProperties)
 {
     var c = new SystemEvent
             {
                 DocumentId = DocumentId,
                 EntityId = EntityId,
                 EntityType = EntityType,
                 Id = Id,
                 Level = Level,
                 LinkId = LinkId,
                 Message = Message,
                 OccurredAt = OccurredAt,
                 ReferenceId = ReferenceId,
                 Source = Source,
                 SystemId = SystemId,
                 Type = Type,
             };
     CopyExtraPropertiesToClone(c, includeLocalProperties);
     return c;
 }