@Override
  public void close() throws IOException {
    if (mUfsInStream.isPresent()) {
      mUfsInStream.get().close();
      mUfsInStream = Optional.empty();
    }
  }
@Test
  public void openClose() throws IOException, AlluxioException {
    AlluxioURI ufsPath = getUfsPath();
    createFile(ufsPath, 0);
    getStream(ufsPath).close();
  }