code: func (vt *VirtualTable) IterRecords(ctx sessionctx.Context, startKey kv.Key, cols []*table.Column,
  	fn table.RecordIterFunc) error {
  	if len(startKey) != 0 {
  		return table.ErrUnsupportedOp
  	}
  	return nil
  }
docs: // IterRecords implements table.Table Type interface.