public List <Attendee> GetAttendees()
        {
            List <Attendee> attendees = new List <Attendee>();

            var participantsPtr = IntPtr.Zero;

            if (!_meetingManager.IsServierStarted)
            {
                return(attendees);
            }

            try
            {
                int maxParticipantCount = 100, getParticipantCount = 0;
                var participantByte     = Marshal.SizeOf(typeof(ParticipantInfo));
                var maxParticipantBytes = participantByte * maxParticipantCount;

                participantsPtr = Marshal.AllocHGlobal(maxParticipantBytes);
                var result = MeetingAgent.GetParticipantsEx(participantsPtr, ref getParticipantCount,
                                                            maxParticipantCount);
                if (result != 0)
                {
                }

                var participants = new List <ParticipantInfo>();
                for (var i = 0; i < getParticipantCount; i++)
                {
                    var pointer     = new IntPtr(participantsPtr.ToInt64() + participantByte * i);
                    var participant =
                        (ParticipantInfo)Marshal.PtrToStructure(pointer, typeof(ParticipantInfo));
                    participants.Add(participant);
                }

                participants.ForEach(p =>
                {
                    attendees.Add(new Attendee()
                    {
                        Id         = p.m_contactInfo.m_szPhoneId,
                        Name       = p.m_contactInfo.m_szDisplayName,
                        IsSpeaking = p.m_bIsSpeaking == 1
                    });
                });

                return(attendees);
            }
            catch (Exception ex)
            {
                Log.Logger.Error($"GetAttendees() excpetion:{ex}");
                return(attendees);
            }
            finally
            {
                if (participantsPtr != IntPtr.Zero)
                {
                    Marshal.FreeHGlobal(participantsPtr);
                }
            }
        }