code: func (mr MutRow) SetRow(row Row) {
  	for colIdx, rCol := range row.c.columns {
  		mrCol := mr.c.columns[colIdx]
  		if rCol.isNull(row.idx) {
  			mrCol.nullBitmap[0] = 0
  			continue
  		}
  		elemLen := len(rCol.elemBuf)
  		if elemLen > 0 {
  			copy(mrCol.data, rCol.data[row.idx*elemLen:(row.idx+1)*elemLen])
  		} else {
  			setMutRowBytes(mrCol, rCol.data[rCol.offsets[row.idx]:rCol.offsets[row.idx+1]])
  		}
  		mrCol.nullBitmap[0] = 1
  	}
  }
docs: // SetRow sets the MutRow with Row.