(a) A spendthrift provision is valid only if it restrains both voluntary and involuntary transfer of a beneficiary's interest.
(b) A term of a trust providing that the interest of a beneficiary is held subject to a "spendthrift trust", or words of similar import, is sufficient to restrain both voluntary and involuntary transfer of the beneficiary's interest.
(c) A beneficiary shall not transfer an interest in a trust in violation of a valid spendthrift provision and, except as otherwise provided in this part, a creditor or assignee of the beneficiary shall not reach the interest or a distribution by the trustee before its receipt by the beneficiary.