code: func NewProbabilisticCounter(cardinality int) *ProbabilisticCounter {
  	return &ProbabilisticCounter{
  		cardinality: cardinality,
  		bitset:      newBitSetForCardinality(cardinality),
  	}
  }
docs: // It creates a new ProbabilisticCounter given an *estimate* of the true cardinality of the set of values it should count.
  // This estimate is needed to that an internal bit map can be initialized and sized properly.