code: func (m *metricUnit) TimeScale() TimeUnit {
  	d := m.TimeDim()
  	if d == 0 {
  		panic("no time scale on unit")
  	}
  
  	return TimeUnit(1<<24 | (uint32((m.repr>>12)&0xF))<<12)
  }
docs: // https://docs.rs/hornet/0.1.0/src/hornet/client/metric/mod.rs.html#398