code: func (r *EtcdRegistry) UnitState(name string) (state *unit.UnitState, err error) {
  	var us *unit.UnitState
  	us, err = r.stateByMUSKey(name)
  	if err != nil {
  		return nil, err
  	}
  
  	return us, nil
  }
docs: // UnitState returns a single UnitState stored in the registry for a given unit
  // name.