code: func NewFilter(capacity uint) *Filter {
  	capacity = getNextPow2(uint64(capacity)) / bucketSize
  	if capacity == 0 {
  		capacity = 1
  	}
  	buckets := make([]bucket, capacity)
  	for i := range buckets {
  		buckets[i] = [bucketSize]byte{}
  	}
  	return &Filter{buckets, 0}
  }
docs: // NewFilter returns a new cuckoofilter with a given capacity.
  // A capacity of 1000000 is a normal default, which allocates
  // about ~1MB on 64-bit machines.