Extended FutureProvider, that displays an additional child while the Future operation is running.

FutureProvider2.dart

import 'package:flutter/widgets.dart';
import 'package:provider/provider.dart';

class FutureProvider2<T> extends FutureProvider<T> {
  final Widget _childOnFutureBusy;

  FutureProvider2.value({
    Key key,
    @required Future<T> value,
    T initialData,
    Widget childOnFutureBusy,
    ErrorBuilder<T> catchError,
    UpdateShouldNotify<T> updateShouldNotify,
    Widget child,
  })  : _childOnFutureBusy = childOnFutureBusy,
        super.value(
            key: key,
            value: value,
            initialData: initialData,
            catchError: catchError,
            updateShouldNotify: updateShouldNotify,
            child: child);

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<T>(
        future: delegate.value,
        initialData: initialData,
        builder: (_, snapshot) {
          return snapshot.connectionState == ConnectionState.waiting
            ? _childOnFutureBusy
            : super.build(context);
        });
  }
}