anchor.diff:  
     Expect.equals(true, nonBlockingFailed);
   
  -  peer.exitCode.then((v) {
  +  await peer.exitCode.then((v) async {
       Expect.equals(0, v);
  -    raf.closeSync();
  -    directory.deleteSync(recursive: true);
  -    asyncEnd();
  +    await raf.close();
  +    await directory.delete(recursive: true);
     });
   }
   
  -main() {
  -  testLockWholeFile();
  +main() async {
  +  asyncStart();
  +  await testLockWholeFile();
  +  asyncEnd();
   }
  
positive.code:   await raf.setPosition(0);
    await raf.lock(FileLock.BLOCKING_EXCLUSIVE, 0, length);
    Process peer = await runPeer(file.path, length, FileLock.BLOCKING_EXCLUSIVE);
  
    // Wait a bit for the other process to get started. We'll synchronize on
    // the file lock.
    await new Future.delayed(const Duration(seconds: 1));
  
    int nextToWrite = 1;
    int at = 0;
  
negative.code: 
  testLockWholeFile() async {
    const int length = 25;
    Directory directory = await Directory.systemTemp.createTemp('dart_file_lock');
    File file = new File(join(directory.path, "file"));
    await file.writeAsBytes(new List.filled(length, 0));
  