func LetterBytes(n int) []byte {
	return randLetterBytes(n)
}
LetterBytes returns a random slice of bytes picked in the [0-9]|[a-z] range
package rand
import (
	"bytes"
	"math/rand"
	"sync"
	"time"
)
func Bytes(n int) []byte {
	return randBytes(n)
}
func String(n int) string {
	return randString(n)
}