anchor.diff:  /// For a future that completes successfully with data, the [builder] may
   /// be called with either both or only the latter of the following snapshots:
   ///
  -/// * `new AsyncSnapshot<String>(ConnectionState.waiting, null, null)`
  -/// * `new AsyncSnapshot<String>(ConnectionState.done, 'some data', null)`
  +/// * `AsyncSnapshot<String>.withData(ConnectionState.waiting, null)`
  +/// * `AsyncSnapshot<String>.withData(ConnectionState.done, 'some data')`
   ///
   /// For a future completing with an error, the [builder] may be called with
   /// either both or only the latter of:
   ///
  -/// * `new AsyncSnapshot<String>(ConnectionState.waiting, null, null)`
  -/// * `new AsyncSnapshot<String>(ConnectionState.done, null, 'some error')`
  +/// * `AsyncSnapshot<String>.withData(ConnectionState.waiting, null)`
  +/// * `AsyncSnapshot<String>.withError(ConnectionState.done, 'some error')`
   ///
   /// The data and error fields of the snapshot change only as the connection
   /// state field transitions from `waiting` to `done`, and they will be retained
  
positive.code: /// A [FutureBuilder] behaves identically to a [StreamBuilder] configured with
  /// `future?.asStream()`, except that snapshots with `ConnectionState.active`
  /// may appear for the latter, depending on how the stream is implemented.
  class FutureBuilder<T> extends StatefulWidget {
    /// Creates a widget that builds itself based on the latest snapshot of
    /// interaction with a [Future].
  
negative.code: /// Changing the [StreamBuilder] configuration to another stream during event
  /// generation introduces snapshot pairs of the form
  ///
  /// * `AsyncSnapshot<int>.withData(ConnectionState.none, 5)`
  /// * `AsyncSnapshot<int>.withData(ConnectionState.waiting, 5)`
  ///
  /// The latter will be produced only when the new stream is non-null. The former
  /// only when the old stream is non-null.
  ///
  /// The stream may produce errors, resulting in snapshots of the form
  ///
  /// * `AsyncSnapshot<int>.withError(ConnectionState.active, 'some error')`
  ///
  /// The data and error fields of snapshots produced are only changed when the
  /// state is `ConnectionState.active`.
  