async getSubscription(id, options = {}) {
        debug(`getSubscription(${id}, ${JSON.stringify(options)})`);
        try {
            await this._rateLimitBucket.throttle();
            const subscription = await this._stripe.subscriptions.retrieve(id, options);
            debug(`getSubscription(${id}, ${JSON.stringify(options)}) -> Success`);
            return subscription;
        } catch (err) {
            debug(`getSubscription(${id}, ${JSON.stringify(options)}) -> ${err.type}`);
            throw err;
        }
    }
Retrieve the Stripe Subscription object by ID.

@param {string} id
@param {ISubscriptionRetrieveParams} options

@returns {Promise<ISubscription>}