code: func (w *wrapper) Devices() map[protocol.DeviceID]DeviceConfiguration {
  	w.mut.Lock()
  	defer w.mut.Unlock()
  	if w.deviceMap == nil {
  		w.deviceMap = make(map[protocol.DeviceID]DeviceConfiguration, len(w.cfg.Devices))
  		for _, dev := range w.cfg.Devices {
  			w.deviceMap[dev.DeviceID] = dev.Copy()
  		}
  	}
  	return w.deviceMap
  }
docs: // Devices returns a map of devices.