code: func init() {
  	if err := initConfig(); err != nil {
  		fmt.Fprintln(os.Stderr, errors.Errorf("error initializing config. maybe PCP isn't installed properly"))
  	}
  
  	var err error
  	histogramIndom, err = NewPCPInstanceDomain("histogram", histogramInstances)
  	if err != nil {
  		fmt.Fprintln(os.Stderr, errors.Errorf("could not initialize an instance domain for histograms"))
  	}
  }
docs: // init maintains a central location of all things that happen when the package is initialized
  // instead of everything being scattered in multiple source files