I have a `TextField` rendered with the help of a `StreamBuilder`, following the `BLoC` pattern with a sink and stream.

```
Widget field(SignUpBloc signUpBloc) {
    return StreamBuilder(
      stream: signUpBloc.outFirstName,
      builder: (context, snapshot) {
        return TextField(
          style: TextStyle(fontSize: 15.0),
          onChanged: signUpBloc.inFirstName,
          decoration: InputDecoration(
            errorStyle: TextStyle(fontSize: 15.0),
            errorText: snapshot.error
          ),
        );
      },
    );
}

```

My question is how do I set up an initial value? I've tried with the `StreamBuilder`'s `initialData` property but no text appears in the `TextField`.