code: func GetNumWorkerMultiplier() int {
  	if gmp := os.Getenv("HUGO_NUMWORKERMULTIPLIER"); gmp != "" {
  		if p, err := strconv.Atoi(gmp); err == nil && p > 0 {
  			return p
  		}
  	}
  	return runtime.NumCPU()
  }
docs: // GetNumWorkerMultiplier returns the base value used to calculate the number
  // of workers to use for Hugo's parallel execution.
  // It returns the value in HUGO_NUMWORKERMULTIPLIER OS env variable if set to a
  // positive integer, else the number of logical CPUs.