code: func (h *Holder) limitedSchema() []*IndexInfo {
  	var a []*IndexInfo
  	for _, index := range h.Indexes() {
  		di := &IndexInfo{
  			Name:       index.Name(),
  			Options:    index.Options(),
  			ShardWidth: ShardWidth,
  		}
  		for _, field := range index.Fields() {
  			if strings.HasPrefix(field.name, "_") {
  				continue
  			}
  			fi := &FieldInfo{Name: field.Name(), Options: field.Options()}
  			di.Fields = append(di.Fields, fi)
  		}
  		sort.Sort(fieldInfoSlice(di.Fields))
  		a = append(a, di)
  	}
  	sort.Sort(indexInfoSlice(a))
  	return a
  }
docs: // limitedSchema returns schema information for all indexes and fields.