func NewZipfianWithRange(min int64, max int64, zipfianConstant float64) *Zipfian {
	return NewZipfian(min, max, zipfianConstant, zetaStatic(0, max-min+1, zipfianConstant, 0))
}
NewZipfianWithRange creates the Zipfian generator.
package generator
import (
	"fmt"
	"math"
	"math/rand"
	"time"
	"github.com/pingcap/go-ycsb/pkg/util"
)
const (
	ZipfianConstant = float64(0.99)
)
type Zipfian struct {
	Number
	lock util.SpinLock
	items int64
	base  int64
	zipfianConstant float64
	alpha      float64
	zetan      float64
	theta      float64
	eta        float64
	zeta2Theta float64
	countForZeta int64
	allowItemCountDecrease bool
}
func NewZipfianWithItems(items int64, zipfianConstant float64) *Zipfian {
	return NewZipfianWithRange(0, items-1, zipfianConstant)
}