checkTTL() {
		let now = Date.now();
		this.cache.forEach((value, key) => {
			let item = this.cache.get(key);

			if (item.expire && item.expire < now) {
				this.logger.debug(`EXPIRED ${key}`);
				this.metrics.increment(METRIC.MOLECULER_CACHER_EXPIRED_TOTAL);
				this.cache.delete(key);
			}
		});
	}
Check & remove the expired cache items

@memberof MemoryCacher