To use the previously cached result (if it exists), use
{@see \Subscription::info()}.
Example:
$subscription->reload();
$info = $subscription->info();
echo $info['name']; // projects/my-awesome-project/subscriptions/my-new-subscription
See also:
https://cloud.google.com/pubsub/docs/reference/rest/v1/projects.subscriptions/get Get Subscription