// Print random int63 number from "mt19937_64".
// Reset random number generator if "i" is 13.
func PrintInt63(i int, mt *rand.Rand, ch chan bool) {
t := rand.Int() % 1000
time.Sleep(time.Duration(t))
if 13 == i {
mt.Seed(12345)
fmt.Printf("13 : (reset) \n")
} else {
fmt.Printf("%2d : %d \n", i, mt.Int63())
}
ch <- true
}