anchor.diff:          _maxSpecialFileSize = maxSpecialFileSize;
   
     /// The current [TarHeader] of the active tar entry.
  -  TarHeader get header {
  -    final header = _header;
  -    if (header == null) {
  -      throw StateError(
  -          'Invalid call to Reader.header, did you call moveNext()?');
  -    }
  -    return header;
  -  }
  +  TarHeader get header => current.header;
   
     /// The content stream of the active tar entry.
     ///
  
positive.code:   /// Skip the next [_skipNext] elements when reading in the stream.
    int _skipNext = 0;
  
    TarHeader? _header;
    Stream<List<int>>? _contents;
    bool _listenedToContents = false;
  
    /// Whether we're in the process of reading tar headers.
    bool _isReadingHeaders = false;
  
negative.code:         }
          nextHeader.format = format;
  
          _current =
              TarEntry(nextHeader, _publishStream(content, nextHeader.size));
          _listenedToContentsOnce = false;
          _currentStreamNullOrComplete = false;
          _isReadingHeaders = false;
          return true;
        }
  