How to use the delay.ts function in delay

let receivedSms;
		let messageListener = evt => {
			receivedSms = evt.body;
			subscription.removeListener('message', messageListener);
			notify('The subscription is alive. Notification delay:' + (Date.now() - sentTime));
			rc.account().extension().messageStore(receivedSms.id).delete({});
			rc.account().extension().messageStore(sentSms.id).delete({});
		};
		subscription.onMessage(messageListener);
		let sentSms = await rc.account().extension().sms().post({
			from: { phoneNumber: config.user.username },
			to: [{ phoneNumber: config.user.username }],
			text: 'Test sms to trigger subscription.'
		});
		let sentTime = Date.now();
		await delay(notificationTimeout * 60 * 1000);
		if (!receivedSms) {
			let msg = 'The notification does not arrive in ' + notificationTimeout + ' minutes.';
			await notify(msg);
			await subscription.cancel();
			process.exit(1);
		}
	}

async call(endpoint: string, query?: {}, opts?: RequestInit): Promise {
		try {
			return await this.sendApiCall(endpoint, query, opts);
		} catch (e) {
			if (this.handleRateLimit && e.code === TOO_MANY_REQUESTS) {
				await delay(e['retryAfter']);
				return await this.call(endpoint, query, opts);
			}
			throw e;
		}
	}