Arguments position error(dart)

Hello everyone, can somebody help me with this error in my home page? In the third Text widget i get an error that says: positional arguments must occur before named arguments

Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Usuários'),
      ),
      body: StreamBuilder(
          stream: FirestoreService().getUsuarios(),
          builder:
              (BuildContext context, AsyncSnapshot<List<Usuario>> snapshot) {
            if (snapshot.hasError || !snapshot.hasData)
              return CircularProgressIndicator();
            return ListView.builder(
                itemCount: snapshot.data.length,
                itemBuilder: (BuildContext context, int index) {
                  Usuario usuario = snapshot.data[index];
                  var listTile = ListTile(
                    title: Text(usuario.nome),
                    subtitle: Container(
                        child: Row(
                      children: <Widget>[
                        Text("Clique para mais detalhes")
                      ],
                    )),
                    trailing: Row(
                      mainAxisSize: MainAxisSize.min,
                      children: <Widget>[
                        IconButton(
                            color: Color.fromRGBO(0, 0, 255, 1.0),
                            icon: Icon(Icons.edit),
                            onPressed: () => Navigator.push(
                                context,
                                MaterialPageRoute(
                                  builder: (_) =>
                                      AddUsuarioPage(usuario: usuario),
                                ))),
                        IconButton(
                          color: Color.fromRGBO(255, 0, 0, 1.0),
                          icon: Icon(Icons.delete),
                          onPressed: () => _excluirUsuario(context, usuario.id),
                        ),
                      ],
                    ),
                    onTap: () => Navigator.push(
                        context,
                        MaterialPageRoute(
                            builder: (_) =>
                                UsuarioDetailsPage(usuario: usuario))),
                  );
                  return listTile;
                });
          }),  
      floatingActionButton: FloatingActionButton(
        child: Icon(Icons.add),
        onPressed: () {
          Navigator.push(
              context, MaterialPageRoute(builder: (_) => AddUsuarioPage()));
        },
      ),
      Text(
  'Hello, How are you?',
  textAlign: TextAlign.center,
  overflow: TextOverflow.ellipsis,
  style: TextStyle(fontWeight: FontWeight.bold),
)
    );
  }