first method
Implementation
Future<T?> first() async {
_ensureNotConsumed();
final sql = _buildSelectSql(overrideLimit: 1);
final raw = await AppAmbitSdkFlutterPlatform.instance
.dbExecute(sql, _whereParams.isEmpty ? null : List.of(_whereParams));
final result = DbResult.fromMap(raw);
if (result.hasError) throw StateError(result.error!);
final maps = result.toMaps();
if (maps.isEmpty) return null;
if (_fromRow != null) return _fromRow(maps.first);
return maps.first as T?;
}