func (c *Config) getRand() *rand.Rand {
	if c.Rand == nil {
		return rand.New(rand.NewSource(time.Now().UnixNano()))
	}
	return c.Rand
}

// getMaxCount returns the maximum number of iterations to run for a given
// Config.
func (c *Config) getMaxCount() (maxCount int) {
	maxCount = c.MaxCount
	if maxCount == 0 {
		if c.MaxCountScale != 0 {
			maxCount = int(c.MaxCountScale * float64(*defaultMaxCount))
		} else {