How to generate model field to a `Map<String, dynamic>` type

I have some logs to display, all the logs will have a `data` field, but different logs may have different `data` structures, I can distinguish them by `type` field but how to mark the `data` filed so that it can be generated to a `Map`. I tried this:

```json
{
"data": {},
"id": "",
"type": ""
}
```

then `get generate model PATH_TO_LOG.json` will lead an error:

```
error_unexpected Could not format because the source could not be parsed:

line 40, column 8: Expected an identifier.
╷
40 │ Data({});
│ ^
╵
```

How to indicate a field that need to be generated to `Map`?