code: func (r Row) GetDuration(colIdx int, fillFsp int) types.Duration {
  	col := r.c.columns[colIdx]
  	dur := *(*int64)(unsafe.Pointer(&col.data[r.idx*8]))
  	return types.Duration{Duration: time.Duration(dur), Fsp: fillFsp}
  }
docs: // GetDuration returns the Duration value with the colIdx.