func (r *Reporter) Discrete(name string, tags []string, val float64) error {
	metricID := instruments.MetricID(name, tags)
	r.refs[metricID] = 2
	r.Metric(name, tags, float32(val))
	return nil
}
func (r *Reporter) Discrete(name string, tags []string, val float64) error {
	metricID := instruments.MetricID(name, tags)
	r.refs[metricID] = 2
	r.Metric(name, tags, float32(val))
	return nil
}
// Discrete implements instruments.Reporter