code: func (d Device) UtilizationRates() (uint, uint, error) {
  	if C.nvmlHandle == nil {
  		return 0, 0, errLibraryNotLoaded
  	}
  	var utilization C.nvmlUtilization_t
  	r := C.nvmlDeviceGetUtilizationRates(d.dev, &utilization)
  	return uint(utilization.gpu), uint(utilization.memory), errorString(r)
  }
docs: // UtilizationRates returns the percent of time over the past sample period during which:
  // utilization.gpu: one or more kernels were executing on the GPU.
  // utilization.memory: global (device) memory was being read or written.