code: func (r Row) GetString(colIdx int) string {
  	col := r.c.columns[colIdx]
  	start, end := col.offsets[r.idx], col.offsets[r.idx+1]
  	str := string(hack.String(col.data[start:end]))
  	return str
  }
docs: // GetString returns the string value with the colIdx.