code: func (c *lruCache) Top() []bitmapPair {
  	a := make([]bitmapPair, 0, len(c.counts))
  	for id, n := range c.counts {
  		a = append(a, bitmapPair{
  			ID:    id,
  			Count: n,
  		})
  	}
  	sort.Sort(bitmapPairs(a))
  	return a
  }
docs: // Top returns all counts in the cache.