using TypetalkSharp;

var typetalk = new TypetalkClient("CLIENT_ID", "CLIENT_SECRET");
var topicId = await typetalk.Topics.All().First(x => x.Name == "TARGET_TOPICS").Topic.Id;
var messages = typetalk.Topics.Messages.Get(topicId);

using TypetalkSharp;

var typetalk = new TypetalkClient("CLIENT_ID", "CLIENT_SECRET");
var topics = await typetalk.Topics.All();
var result = typetalk.Topics.Messages.Post(
					topics.First(x => x.Name == "TARGET_TOPICS").Topic.Id,
					new NewMessage("message from TypetalkSharp!"));

using TypetalkSharp.Bot;

var typetalkBot = new TypetalkBot("YOUR_TYPETALK_TOKEN");
var topicId = 0;
var result = await typetalk.Topics.Messages.Post(topicId, new NewMessage("from TypetalkSharp!"));