in retry.go [88:98]
func (sr *statelessRetryer) pause() time.Duration {
jitter := sr.jitter.Nanoseconds()
if jitter > 0 {
sr.mu.Lock()
jitter = sr.r.Int63n(jitter)
sr.mu.Unlock()
}
pause := sr.minBackoff.Nanoseconds() + jitter
return time.Duration(pause)
}