addRow method
Adds a new row. Throws if the row length doesn't match columns.
Implementation
void addRow(List<dynamic> row) {
if (row.length != columns.length) {
throw ArgumentError(
'Row length (${row.length}) must match columns length (${columns.length}).');
}
rows.add(row);
if (_schema != null) {
_verifyRowTypes(row);
}
}