func (e GaugeDelta) Key() string {
	return e.Name
}
Key returns the name of this metric
package event
import "fmt"
type GaugeDelta struct {
	Name  string
	Value int64
}
func (e *GaugeDelta) Update(e2 Event) error {
	if e.Type() != e2.Type() {
		return fmt.Errorf("statsd event type conflict: %s vs %s ", e.String(), e2.String())
	}
	e.Value += e2.Payload().(int64)
	return nil
}
func (e GaugeDelta) Payload() interface{} {
	return e.Value
}
func (e GaugeDelta) Stats() []string {
	if e.Value < 0 {
		return []string{
			fmt.Sprintf("%s:%d|g", e.Name, 0),
			fmt.Sprintf("%s:%d|g", e.Name, e.Value),
		}
	}
	return []string{fmt.Sprintf("%s:+%d|g", e.Name, e.Value)}
}