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 the next app tag for a given sender and recipient pair.
Gets the sender for tags.
Notifies the simulator that a note has been created, so that it can be returned in future read requests in the same
transaction. This note should only be added to the non-volatile database if found in an actual block.
Notifies the simulator that a non-note nullifier has been created, so that it can be used for note nonces.
Notifies the simulator that a note has been nullified, so that it is no longer returned in future read requests in
the same transaction. This note should only be removed to the non-volatile database if its nullifier is found in an
actual block.
Sets the sender for tags.