anchor.diff:  /// Futures are often used for potentially lengthy computations
   /// such as I/O and interaction with users.
   ///
  -/// Many methods in the Dart libraries return Futures when
  -/// performing tasks. For example, when binding an HttpServer
  +/// Many methods in the Dart libraries return `Future`s when
  +/// performing tasks. For example, when binding an `HttpServer`
   /// to a host and port, the `bind()` method returns a Future.
   /// ```dart
   ///  HttpServer.bind('127.0.0.1', 4444)
  
positive.code: /// Support for asynchronous programming,
  /// with classes such as Future and Stream.
  ///
  /// Understanding [Future]s and [Stream]s is a prerequisite for
  /// writing just about any Dart program.
  ///
  /// To use this library in your code:
  /// ```dart
  
negative.code: /// contents of a file
  /// such as mouse clicks, and a stream of byte lists read from a file.
  /// The following example opens a file for reading.
  /// [Stream.listen] registers callback functions that run
  /// each time more data is available, an error has occurred, or
  /// the stream has finished.
  /// Further functionality is provided on [Stream], implemented by calling
  /// [Stream.listen] to get the actual data.
  /// ```dart
  /// Stream<List<int>> stream = File('quotes.txt').openRead();
  /// stream.transform(utf8.decoder).forEach(print);
  /// ```
  /// This stream emits a sequence of lists of bytes.
  /// The program must then handle those lists of bytes in some way.
  /// Here, the code uses a UTF-8 decoder (provided in the `dart:convert` library)
  /// to convert the sequence of bytes into a sequence
  /// of Dart strings.
  