code: func (v *view) max(filter *Row, bitDepth uint) (max, count uint64, err error) {
  	for _, f := range v.allFragments() {
  		fmax, fcount, err := f.max(filter, bitDepth)
  		if err != nil {
  			return max, count, err
  		}
  		if fcount > 0 && fmax > max {
  			max = fmax
  			count += fcount
  		}
  	}
  	return max, count, nil
  }
docs: // max returns the max and count of a field.