public MemberJoinEvent(WebhookEventSource source, long timestamp, string replyToken, IList <WebhookEventSource> members)
     : base(WebhookEventType.MemberJoined, source, timestamp, replyToken)
 {
     Joined = new Moved(members);
 }
 public WebhookEvent(WebhookEventType type, WebhookEventSource source, long timestamp)
 {
     Type      = type;
     Source    = source;
     Timestamp = timestamp;
 }
 public MemberLeaveEvent(WebhookEventSource source, long timestamp, IList <WebhookEventSource> members)
     : base(WebhookEventType.MemberLeft, source, timestamp)
 {
     Left = new Moved(members);
 }