code: func (b *Builder) DiskUsage(ctx context.Context) ([]*types.BuildCache, error) {
  	duResp, err := b.controller.DiskUsage(ctx, &controlapi.DiskUsageRequest{})
  	if err != nil {
  		return nil, err
  	}
  
  	var items []*types.BuildCache
  	for _, r := range duResp.Record {
  		items = append(items, &types.BuildCache{
  			ID:          r.ID,
  			Parent:      r.Parent,
  			Type:        r.RecordType,
  			Description: r.Description,
  			InUse:       r.InUse,
  			Shared:      r.Shared,
  			Size:        r.Size_,
  			CreatedAt:   r.CreatedAt,
  			LastUsedAt:  r.LastUsedAt,
  			UsageCount:  int(r.UsageCount),
  		})
  	}
  	return items, nil
  }
docs: // DiskUsage returns a report about space used by build cache