writeAsString method
Implementation
Future<void> writeAsString(String contents) async {
final db = await _openDb();
final txn = db.transaction(_objectStoreName, idbModeReadWrite);
final store = txn.objectStore(_objectStoreName);
await store.put({
_propNameFilePath: _filePath,
_propNameFileContents: contents
}); // if the file exists, it will be replaced.
await txn.completed;
}