internal void JoinMessaging(string channelUrl)
        {
            var    intent = new Intent(this, typeof(SendBirdMessagingActivity));
            Bundle args   = SendBirdMessagingActivity.MakeMessagingJoinArgs(appId, userId, userName, channelUrl);

            intent.PutExtras(args);
            StartActivityForResult(intent, REQUEST_SENDBIRD_MESSAGING_ACTIVITY);
        }
        internal void StartMessaging(string[] targetUserIds)
        {
            var    intent = new Intent(this, typeof(SendBirdMessagingActivity));
            Bundle args   = SendBirdMessagingActivity.MakeMessagingStartArgs(appId, userId, userName, targetUserIds);

            intent.PutExtras(args);
            StartActivityForResult(intent, REQUEST_SENDBIRD_MESSAGING_ACTIVITY);
        }