long getHardDeleteProgress() {
      return index.hardDeleter.getProgress();
    }
Always returns a {@link FindTokenType#Uninitialized} token.
@param token the {@link StoreFindToken} to revalidate.
@return a {@link FindTokenType#Uninitialized} token.
ambry-store/src/test/java/com/github/ambry/store/HardDeleterTest.java