joinChat(steamID, callback) {
		return StdLib.Promises.callbackPromise([], callback, true, (resolve, reject) => {
			let msg = ByteBuffer.allocate(9, ByteBuffer.LITTLE_ENDIAN);
			msg.writeUint64(toChatID(steamID).getSteamID64()); // steamIdChat
			msg.writeUint8(0); // isVoiceSpeaker
			this._send(EMsg.ClientJoinChat, msg.flip());

			Helpers.onceTimeout(10000, this, 'chatEnter#' + Helpers.steamID(steamID).getSteamID64(), (err, chatID, result) => {
				err = err || Helpers.eresultError(result);
				if (err) {
					return reject(err);
				} else {
					return resolve();
				}
			});
		});
	}
Join a chat room. To join a group chat, use the group's (clan) SteamID.
@param {(SteamID|string)} steamID - The SteamID of the chat to join (as a SteamID object or a string which can parse into one)
@param {SteamUser~genericEResultCallback} [callback] - An optional callback to be invoked when the room is joined (or a failure occurs).
@return Promise
@deprecated This uses the old-style chat rooms, if you want new chat instead use this.chat