anchor.diff:  /// the inherited variables.
   Future<PubProcessResult> runProcess(String executable, List<String> args,
       {workingDir, Map<String, String> environment}) {
  -  // TODO(nweiz): use _descriptorPool here.
  -  return _doProcess(Process.run, executable, args, workingDir, environment)
  -      .then((result) {
  -    // TODO(rnystrom): Remove this and change to returning one string.
  -    List<String> toLines(String output) {
  -      var lines = splitLines(output);
  -      if (!lines.isEmpty && lines.last == "") lines.removeLast();
  -      return lines;
  -    }
  -
  -    var pubResult = new PubProcessResult(toLines(result.stdout),
  -                                toLines(result.stderr),
  -                                result.exitCode);
  -
  -    log.processResult(executable, pubResult);
  -    return pubResult;
  +  return _descriptorPool.withResource(() {
  +    return _doProcess(Process.run, executable, args, workingDir, environment)
  +        .then((result) {
  +      // TODO(rnystrom): Remove this and change to returning one string.
  +      List<String> toLines(String output) {
  +        var lines = splitLines(output);
  +        if (!lines.isEmpty && lines.last == "") lines.removeLast();
  +        return lines;
  +      }
  +
  +      var pubResult = new PubProcessResult(toLines(result.stdout),
  +                                  toLines(result.stderr),
  +                                  result.exitCode);
  +
  +      log.processResult(executable, pubResult);
  +      return pubResult;
  +    });
     });
   }
   
  
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);
  