fllutter builder void code example

Example: flutter future builder

FutureBuilder(
        future: _fetchNetworkCall, // async work
        builder: (BuildContext context, AsyncSnapshot snapshot) {
           switch (snapshot.connectionState) {
             case ConnectionState.waiting: return Text('Loading....');
             default:
               if (snapshot.hasError)
                  return Text('Error: ${snapshot.error}');
               else
              return Text('Result: ${snapshot.data}');
            }
         },
        ),