anchor.diff:    /// writes it to [_buffer].
     ///
     /// Returns true if the [nextCodeUnit] was combined with the
  -  /// [leadingSurrogate]. If it wasn't then nextCodeUnit was not a trailing
  +  /// [leadingSurrogate]. If it wasn't, then nextCodeUnit was not a trailing
     /// surrogate and has not been written yet.
     ///
  -  /// It is safe to pass 0 for [nextCodeUnit] in which case a replacement
  +  /// It is safe to pass 0 for [nextCodeUnit], in which case a replacement
     /// character is written to represent the unpaired lead surrogate.
     bool _writeSurrogate(int leadingSurrogate, int nextCodeUnit) {
       if (_isTailSurrogate(nextCodeUnit)) {
  
positive.code:   const Utf8Codec({bool allowMalformed = false})
        : _allowMalformed = allowMalformed;
  
    /// The name of this codec, "utf-8".
    String get name => "utf-8";
  
    /// Decodes the UTF-8 [codeUnits] (a list of unsigned 8-bit integers) to the
  
negative.code: 
  /// This class converts strings to their UTF-8 code units (a list of
  /// unsigned 8-bit integers).
  ///
  /// Example:
  /// ```dart
  /// final utf8Encoder = utf8.encoder;
  /// const sample = 'Îñţérñåţîöñåļîžåţîờñ';
  /// final encodedSample = utf8Encoder.convert(sample);
  /// print(encodedSample);
  /// ```
  class Utf8Encoder extends Converter<String, List<int>> {
    const Utf8Encoder();
  
  