anchor.diff:    /// Encoders will not accept invalid (non ASCII) characters.
     const AsciiCodec({bool allowInvalid = false}) : _allowInvalid = allowInvalid;
   
  -  /// The name of this codec, "us-ascii".
  +  /// The name of this codec is "us-ascii".
     String get name => "us-ascii";
   
     Uint8List encode(String source) => encoder.convert(source);
  
positive.code:   Stream<String> bind(Stream<List<int>> stream) => super.bind(stream);
  }
  
  class AsciiDecoder extends _UnicodeSubsetDecoder {
    const AsciiDecoder({bool allowInvalid = false})
        : super(allowInvalid, _asciiMask);
  
negative.code:   Stream<List<int>> bind(Stream<String> stream) => super.bind(stream);
  }
  
  /// Converts strings of only ASCII characters to bytes.
  ///
  /// Example:
  /// ```dart import:typed_data
  /// const asciiEncoder = AsciiEncoder();
  /// const sample = 'Dart';
  /// final asciiValues = asciiEncoder.convert(sample);
  /// print(asciiValues); // [68, 97, 114, 116]
  /// ```
  class AsciiEncoder extends _UnicodeSubsetEncoder {
    const AsciiEncoder() : super(_asciiMask);
  }
  