code: public PubsubFuture<Subscription> getSubscription(final String canonicalSubscriptionName) {
      validateCanonicalSubscription(canonicalSubscriptionName);
      return get("get subscription", canonicalSubscriptionName, readJson(Subscription.class));
    }
docs: Get a Pub/Sub subscription.
  
  @param canonicalSubscriptionName The canonical (including project) name of the subscription to get.
  @return A future that is completed when this request is completed. The future will be completed with {@code null}
  if the response is 404.