public async void Chatter_Add_Comment()
        {
            var feedItem = await postFeedItem(_chatterClient);
            var feedId = feedItem.id;

            var messageSegment = new MessageSegmentInput
            {
                text = "Comment testing 1, 2, 3",
                type = "Text"
            };

            var body = new MessageBodyInput { messageSegments = new List<MessageSegmentInput> { messageSegment } };
            var commentInput = new FeedItemInput
            {
                attachment = null,
                body = body
            };

            var comment = await _chatterClient.PostFeedItemCommentAsync<Comment>(commentInput, feedId);
            Assert.IsNotNull(comment);
        }
        public async void Chatter_Add_Comment_With_Mention_IsNotNull()
        {
            var feedItem = await postFeedItem(_chatterClient);
            var feedId = feedItem.id;

            var me = await _chatterClient.MeAsync<UserDetail>();
            var meId = me.id;

            var messageSegment1 = new MessageSegmentInput
            {
                id = meId,
                type = "Mention",
            };

            var messageSegment2 = new MessageSegmentInput
            {
                text = "Comment testing 1, 2, 3",
                type = "Text",
            };

            var body = new MessageBodyInput
            {
                messageSegments = new List<MessageSegmentInput>
                {
                    messageSegment1, 
                    messageSegment2
                }
            };
            var commentInput = new FeedItemInput
            {
                attachment = null,
                body = body
            };

            var comment = await _chatterClient.PostFeedItemCommentAsync<Comment>(commentInput, feedId);
            Assert.IsNotNull(comment);
        }
        private async Task<FeedItem> postFeedItem(ChatterClient chatter)
        {
            var me = await chatter.MeAsync<UserDetail>();
            var id = me.id;

            var messageSegment = new MessageSegmentInput
            {
                text = "Testing 1, 2, 3",
                type = "Text"
            };

            var body = new MessageBodyInput { messageSegments = new List<MessageSegmentInput> { messageSegment } };
            var feedItemInput = new FeedItemInput()
            {
                attachment = null,
                body = body
            };

            var feedItem = await chatter.PostFeedItemAsync<FeedItem>(feedItemInput, id);
            return feedItem;
        }