create method
Creates this entry within the parent directory, which defaults to
sandbox.
Implementation
@override
Future<void> create([String? parent]) async {
// Create the stream before we call [File.openWrite] because it may fail
// fast (e.g. if this is a matcher file).
final file = File(p.join(parent ?? sandbox, name)).openWrite();
try {
await readAsBytes().forEach(file.add);
} finally {
await file.close();
}
}