@Nullable
  public static String md5(@NotNull VirtualFile file) {
    try {
      MessageDigest md5 = DigestUtil.md5();
      md5.update(file.contentsToByteArray());
      final byte[] digest = md5.digest();

      return BaseEncoding.base16().lowerCase().encode(digest);
    }
    catch (Exception e) {
      return null;
    }
  }
@Nullable
  public static String md5(@NotNull VirtualFile file)