anchor.diff:            '${Strings.join(result.stdout, "\n")}\n'
             '${Strings.join(result.stderr, "\n")}';
       }
  -
       // Find the tar file we just created since we don't know its name.
       return listDir(tempDir);
     }).chain((files) {
  
positive.code:     // Write the archive to a temp file.
      tempDir = temp;
      return createFileFromStream(stream, join(tempDir, 'data.tar.gz'));
    }).chain((tarGz) {
      // 7zip can't unarchive from gzip -> tar -> destination all in one step
      // first we un-gzip it to a tar file.
      // Note: Setting the working directory instead of passing in a full file
  
negative.code:   }).chain((result) {
      if (result.exitCode != 0) {
        throw 'Could not un-tar (exit code ${result.exitCode}). Error:\n'
            '${Strings.join(result.stdout, "\n")}\n'
            '${Strings.join(result.stderr, "\n")}';
      }
  
  