Returns true if the nullifier exists. Note that a true value can be constrained by proving existence of the
nullifier, but a false value should not be relied upon since other transactions may emit this nullifier before the
current transaction is included in a block. While this might seem of little use at first, certain design patterns
benefit from this abstraction (see e.g. PrivateMutable).
Returns true if the nullifier exists. Note that a
truevalue can be constrained by proving existence of the nullifier, but afalsevalue should not be relied upon since other transactions may emit this nullifier before the current transaction is included in a block. While this might seem of little use at first, certain design patterns benefit from this abstraction (see e.g.PrivateMutable).