what is the use of futurebuilder in flutter code example

Example 1: flutter future builder

FutureBuilder<String>(
        future: _fetchNetworkCall, // async work
        builder: (BuildContext context, AsyncSnapshot<String> 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}');
            }
         },
        ),

Example 2: future builder flutter

class ProjectModel {  String id;  String createdOn;  String lastModifiedOn;  String title;  String description;  ProjectModel({    this.id,    this.createdOn,    this.lastModifiedOn,    this.title,    this.description,  });}