private void AddEventAttendees(IEnumerable <Attendee> recipients, Event googleEvent, bool optional)
        {
            IEnumerable <Attendee> recipeintList = recipients as IList <Attendee> ??
                                                   recipients.Take(maxAttendees).ToList();

            if (!recipeintList.Any() && googleEvent == null)
            {
                return;
            }

            foreach (var recipient in recipeintList)
            {
                //Ignore recipients with invalid Email
                if (!recipient.Email.IsValidEmailAddress())
                {
                    continue;
                }
                var eventAttendee = new EventAttendee
                {
                    DisplayName    = recipient.Name,
                    Email          = recipient.Email,
                    Optional       = optional,
                    ResponseStatus = AppointmentHelper.GetGoogleResponseStatus(recipient.MeetingResponseStatus)
                };
                googleEvent.Attendees.Add(eventAttendee);
            }
        }
        private void GetAttendees(Event googleEvent, List <Attendee> recipients, bool isOptional)
        {
            if (googleEvent != null && googleEvent.Attendees != null)
            {
                var attendees =
                    googleEvent.Attendees.Where(attendee => attendee.Optional.GetValueOrDefault() == isOptional);

                foreach (var eventAttendee in attendees)
                {
                    recipients.Add(new Attendee
                    {
                        Name = eventAttendee.DisplayName, Email = eventAttendee.Email,
                        MeetingResponseStatus = AppointmentHelper.GetGoogleResponseStatus(eventAttendee.ResponseStatus)
                    });
                }
            }
        }