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