Erro na classe ListaTransferencia

Ola Prof, Estou pegando este erro, tentei fazer o mesmo da duvida já apontada abaixo, mas não deu certo.

class ListaTransferencias extends StatelessWidget{

  final List<Transferencia> _transferencias = [];

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Scaffold(
      appBar: AppBar(
        backgroundColor: primaryColor,
        title: Text('Transferências'),
      ),
      body: ListView.builder(
        itemCount: _transferencias.length,
        itemBuilder: (context, indice) {
          final transferencia = _transferencias[indice];
          return ItemTransferencia(transferencia);
        },
      ),
      floatingActionButtonLocation: FloatingActionButtonLocation.endDocked,
      floatingActionButton: FloatingActionButton(
        child: Icon(Icons.add),
        backgroundColor: Colors.green,
        onPressed: () {
          final Future<Transferencia> future =
          Navigator.push(context, MaterialPageRoute(builder: (context) {
            return FormularioTransferencia();
          }));
          future.then((transferenciaRecebida) {
            debugPrint('chegou no then do future');
            debugPrint('$transferenciaRecebida');
            _transferencias.add(transferenciaRecebida);
          });
      },),
      bottomNavigationBar: BottomAppBar(
          shape: CircularNotchedRectangle(),
          color: primaryColor,
          child: Container(height: 50)
      ),
    );
  }
}

Performing hot reload... Syncing files to device AOSP on IA Emulator... lib/main.dart:107:21: Error: A value of type 'Future' can't be assigned to a variable of type 'Future'.

• 'Future' is from 'dart:async'.
• 'Transferencia' is from 'package:bytebank/main.dart' ('lib/main.dart').

     Navigator.push(context, MaterialPageRoute(builder: (context) {
               ^