uptime

type ContinuousFactory struct{}

type Factory interface {
	// New returns a new meter with the provided halflife.
	New(halflife time.Duration) Meter
}

type IntervalFactory struct{}

type Meter interface {
	// Start the meter, the read value will be monotonically increasing while
	// the meter is running.
	Start(time.Time)

	// Stop the meter, the read value will be exponentially decreasing while the
	// meter is off.
	Stop(time.Time)

	// Read the current value of the meter, this can be used to approximate the
	// percent of time the meter has been running recently. The definition of
	// recently depends on the halflife of the decay function.
	Read(time.Time) float64
}