src/server/pkg/backoff/exponential.go
func (b *ExponentialBackOff) NextBackOff() time.Duration {
	// Make sure we have not gone over the maximum elapsed time.
	if b.MaxElapsedTime != 0 && b.GetElapsedTime() > b.MaxElapsedTime {
		return Stop
	}
	defer b.incrementCurrentInterval()
	return getRandomValueFromInterval(b.RandomizationFactor, rand.Float64(), b.currentInterval)
}
func (b *ExponentialBackOff) NextBackOff() time.Duration {
	// Make sure we have not gone over the maximum elapsed time.
	if b.MaxElapsedTime != 0 && b.GetElapsedTime() > b.MaxElapsedTime {
		return Stop
	}
	defer b.incrementCurrentInterval()
	return getRandomValueFromInterval(b.RandomizationFactor, rand.Float64(), b.currentInterval)
}
// NextBackOff calculates the next backoff interval using the formula:
// 	Randomized interval = RetryInterval +/- (RandomizationFactor * RetryInterval)