anchor.diff:        throw new Exception("Failed to extract .tar.gz stream to $destination "
             "(exit code $exitCode).");
       }
  -    log.fine("Extracted .tar.gz stream to $destination. Exit code "
  -        "$exitCode.");
  +    log.fine("Extracted .tar.gz stream to $destination. Exit code $exitCode.");
     });
   }
   
  
positive.code: /// Writes [stream] to a new file at path [file]. Will replace any file already
  /// at that path. Completes when the file is done being written.
  Future<String> createFileFromStream(Stream<List<int>> stream, String file) {
    log.io("Creating $file from stream.");
  
    return _descriptorPool.withResource(() {
      return stream.pipe(new File(file).openWrite()).then((_) {
        log.fine("Created $file from stream.");
        return file;
      });
  
negative.code:     // Write the archive to a temp file.
      var dataFile = path.join(tempDir, 'data.tar.gz');
      return createFileFromStream(stream, dataFile).then((_) {
        // TODO(nweiz): remove this when we're finished debugging the windows
        // bots.
        log.io("Does $dataFile exist? ${fileExists(dataFile)}");
        try {
          readBinaryFile(dataFile);
  