def __init__(self, to: int, timestamp: int, rr_update: dict):
self._qtime = int(time())<EOL>self._timestamp = timestamp<EOL>self._to = to<EOL>self._rr_update = rr_update<EOL>
Initialize a new revocation registry update frame for revocation cache.

:param to: the time (epoch sec) of interest
:param timestamp: the timestamp (epoch sec) corresponding to the revocation delta on the ledger
:param rr_update: the indy-sdk revocation registry delta or state update