code: func (ts *TiDBStatement) StoreResultSet(rs ResultSet) {
  	// refer to https://dev.mysql.com/doc/refman/5.7/en/cursor-restrictions.html
  	// You can have open only a single cursor per prepared statement.
  	// closing previous ResultSet before associating a new ResultSet with this statement
  	// if it exists
  	if ts.rs != nil {
  		terror.Call(ts.rs.Close)
  	}
  	ts.rs = rs
  }
docs: // StoreResultSet stores ResultSet for stmt fetching