using _sumo_metadata with non json logs

hello, we'd like to use `_sumo_metadata`, but we currently send our logs as text only. would it be possible to send a message like this:

```
{
  _sumo_metadata: {...},
  message: 'stuff'
}
```

and have the log appear as just 'stuff' as text, instead of `{message: 'stuff'}` on sumo? if not, then would you be open to adding a flag and some code to facilitate it? 

Thanks!