backoff

type Backoff interface {
	// Duration returns the duration to wait before retrying the operation.
	// Duration accepts the number of times the operation has been retried.
	// If the operation has never been retried, the number should be 0.
	Duration(int) time.Duration
}

type ConstantBackoff struct {
	Interval time.Duration
}

type ExponentialBackoff struct {
	Interval time.Duration
	Base     int
}

type ScheduledBackoff struct {
	Schedule []time.Duration
}