anchor.diff:  /// of the following snapshots that includes the last one (the one with
   /// ConnectionState.done):
   ///
  -/// * `AsyncSnapshot<int>.withData(ConnectionState.waiting, null)`
  -/// * `AsyncSnapshot<int>.withData(ConnectionState.active, 0)`
  -/// * `AsyncSnapshot<int>.withData(ConnectionState.active, 1)`
  +/// * `new AsyncSnapshot<int>.withData(ConnectionState.waiting, null)`
  +/// * `new AsyncSnapshot<int>.withData(ConnectionState.active, 0)`
  +/// * `new AsyncSnapshot<int>.withData(ConnectionState.active, 1)`
   /// * ...
  -/// * `AsyncSnapshot<int>.withData(ConnectionState.active, 9)`
  -/// * `AsyncSnapshot<int>.withData(ConnectionState.done, 9)`
  +/// * `new AsyncSnapshot<int>.withData(ConnectionState.active, 9)`
  +/// * `new AsyncSnapshot<int>.withData(ConnectionState.done, 9)`
   ///
   /// The actual sequence of invocations of [build] depends on the relative timing
   /// of events produced by the stream and the build rate of the Flutter pipeline.
  
positive.code: ///         else
  ///           return new Text('Result: ${snapshot.data}');
  ///     }
  ///   }
  ///
  ///   @override
  ///   Widget build(BuildContext context) {
  ///     return new Scaffold(
  ///       body: new Center(
  ///         child: new FutureBuilder(
  ///           future: _calculation,
  ///           builder: _buildCalculationWidget,
  ///         ),
  ///       ),
  ///       floatingActionButton: new FloatingActionButton(
  ///         onPressed: _initiateCalculation,
  ///         child: new Icon(Icons.forward),
  ///       ),
  ///     );
  ///   }
  /// }
  /// ```
  class FutureBuilder<T> extends StatefulWidget {
    /// Creates a widget that builds itself based on the latest snapshot of
  
negative.code: ///
  /// ## Sample code
  ///
  /// This sample shows a [FutureBuilder] configuring a text label to show the
  /// state of an asynchronous calculation returning a string. Assume the
  /// `_calculation` field is set by pressing a button elsewhere in the UI.
  ///
  /// ```dart
  /// new FutureBuilder<String>(
  ///   future: _calculation, // a Future<String> or null
  ///   builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
  ///     switch (snapshot.connectionState) {
  ///       case ConnectionState.none: return new Text('Press button to start');
  ///       case ConnectionState.waiting: return new Text('Awaiting result...');
  