anchor.diff:      // Write the archive to a temp file.
       tempDir = temp;
       return createFileFromStream(stream, join(tempDir, 'data.tar.gz'));
  -  }).chain((tarGz) {
  +  }).chain((_) {
  +    // TODO(rnystrom): Hack. We get intermittent "file already in use" errors.
  +    // It looks like the 7zip process is starting up before the file has
  +    // finished being written. So we'll just sleep for a couple of seconds
  +    // here. :(
  +    return sleep(2000);
  +  }).chain((_) {
       // 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
  
positive.code:           '${Strings.join(result.stdout, "\n")}\n'
            '${Strings.join(result.stderr, "\n")}';
      }
  
      // Find the tar file we just created since we don't know its name.
      return listDir(tempDir);
    }).chain((files) {
  
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")}';
      }
  
  