WB Sharing/Network page: Flexible space bar and contextual app bar

[saachipahwa]

https://api.flutter.dev/flutter/material/FlexibleSpaceBar-class.html where instead of the header being a picture, we could give a paragraph or two of explanation, that will conveniently disappear when scrolled down.

if we do add the app bar we can then also use contextual action bar later to provide a convenient way to delete friends.

[saachipahwa]

My attempt:

final customScrollFriendsWidget = FutureBuilder(
        future: friendsList,
        builder: (ctx, data) {
          final List<Friend> friends = data.data;
          return !data.hasData || friends.length == 0
              ? noFriendsWidget
              : Column(children: [
                  CustomScrollView(slivers: [
                    SliverAppBar(
                      expandedHeight: 30.0,
                      flexibleSpace: const FlexibleSpaceBar(
                          title: Text(
                        "With NudgeMe, caring is sharing. \n\nLet people in your care network know how you are to start meaningful and helpful conversations about wellbeing. \n\n" +
                            "Click the send button below to share your diary with your network or to send a nudge. Sending a nudge to someone in your care network allows you to set them a steps goal. View other people’s wellbeing and diaries and nudges with the View button.\n\n" +
                            "Pull down to reload.",
                      )),
                    ),
                    SliverToBoxAdapter(child: friendsListWidget),
                  ]),
                  SliverToBoxAdapter(child: friendsButtonsWidget)
                ]);
        });

The problem is that they last 2 things aren't slivers