Except as to withholding of any tax under the laws of the United States or any state or locality, no benefit payable at any time hereunder shall be subject in any manner to alienation, sale, transfer, assignment, pledge, attachment or other legal process, or encumbrance of any kind. Any attempt to alienate, sell, transfer, assign, pledge or otherwise encumber any such benefit, whether currently or thereafter payable hereunder, shall be void.