code: func (d Device) FanSpeed() (uint, error) {
  	if C.nvmlHandle == nil {
  		return 0, errLibraryNotLoaded
  	}
  	var n C.uint
  	r := C.nvmlDeviceGetFanSpeed(d.dev, &n)
  	return uint(n), errorString(r)
  }
docs: // FanSpeed returns the temperature for this GPU in the percentage of its full
  // speed, with 100 being the maximum.