code: func NewDefault(prof *profile.Profile, options Options) *Report {
  	index := len(prof.SampleType) - 1
  	o := &options
  	if o.Title == "" && len(prof.Mapping) > 0 && prof.Mapping[0].File != "" {
  		o.Title = filepath.Base(prof.Mapping[0].File)
  	}
  	o.SampleType = prof.SampleType[index].Type
  	o.SampleUnit = strings.ToLower(prof.SampleType[index].Unit)
  	o.SampleValue = func(v []int64) int64 {
  		return v[index]
  	}
  	return New(prof, o)
  }
docs: // NewDefault builds a new report indexing the last sample value
  // available.