Dart: Sequential file write/delete operations

file_test.dart

import 'dart:io';

Future<int> saveDelete(int i) {
  var completer = new Completer();
  var path = new Path.fromNative(r'D:\test.txt');
  var file = new File.fromPath(path);
  var outputStream = file.openOutputStream();
  if (outputStream.writeString('Hello World!')) {
    outputStream.close();
  } else {
    outputStream.onClosed = () {
      file.delete().then((success) {
        completer.complete(i);
      });
    };
    outputStream.onNoPendingWrites = () {
      outputStream.close();
    };
  }
  return completer.future;
}

main() {
  Future<int> future = saveDelete(0);
  for (int i = 0; i < 1000; i++) {
    future = future.chain((value) => saveDelete(i));
  }
  future.then((value) => print('$value ready!'));
}