histogram.go
func (m *CirconusMetrics) RecordCountForValue(metric string, val float64, n int64) {
	hist := m.NewHistogram(metric)

	m.hm.Lock()
	hist.rw.Lock()
	hist.hist.RecordValues(val, n)
	hist.rw.Unlock()
	m.hm.Unlock()
}
func (m *CirconusMetrics) RecordCountForValue(metric string, val float64, n int64) {
	hist := m.NewHistogram(metric)

	m.hm.Lock()
	hist.rw.Lock()
	hist.hist.RecordValues(val, n)
	hist.rw.Unlock()
	m.hm.Unlock()
}
// RecordCountForValue adds count n for value to a histogram