code: func (pc *ProbabilisticCounter) Count() int {
  	ones := float64(pc.bitset.Count())
  	length := float64(pc.bitset.Len())
  	zeroes := length - ones
  	estimator := -1 * length * math.Log(zeroes/length)
  	return int(estimator)
  }
docs: // It provides an (approximate) distinct count of values counter so far, with an error rate less than 1.25% on average.