code: func (m *metricUnit) CountScale() CountUnit {
  	d := m.CountDim()
  	if d == 0 {
  		panic("no count scale on unit")
  	}
  
  	return CountUnit(1<<20 | (uint32((m.repr>>8)&0xF))>>8)
  }
docs: // https://docs.rs/hornet/0.1.0/src/hornet/client/metric/mod.rs.html#398