code: func (d *Flags) Init(f *flag.FlagSet) {
  	f.BoolVar(&d.Quiet, "quiet", false, "Get less output")
  	f.BoolVar(&d.Verbose, "verbose", false, "Get more output")
  	f.StringVar(&d.TracePath, "trace", "", "Name of trace file to generate")
  }
docs: // Init registers flags in a given flag set.