code: func (c *Cache) isEntryExpired(now time.Time, ent *cacheEntry) bool {
  	return !(ent.expiry.IsZero() || now.Before(ent.expiry))
  }
docs: // isEntryExpired returns whether this entry is expired given the current time.
  //
  // An entry is expired if it has an expiration time, and the current time is >=
  // the expiration time.
  //
  // Will return false if the entry has no expiration, or if the entry is not
  // expired.