func GetOrRegisterMeter(name string, r Registry) Meter {
	if nil == r {
		r = DefaultRegistry
	}
	return r.GetOrRegister(name, NewMeter).(Meter)
}
GetOrRegisterMeter returns an existing Meter or constructs and registers a
new StandardMeter.
Be sure to unregister the meter from the registry once it is of no use to
allow for garbage collection.
package metrics
import (
	"math"
	"sync"
	"sync/atomic"
	"time"
)
type Meter interface {
	Count() int64
	Mark(int64)
	Rate1() float64
	Rate5() float64
	Rate15() float64
	RateMean() float64
	Snapshot() Meter
	Stop()
}