### Question:
Replicator implements ThreadId.OnError { public static boolean stop(final ThreadId id) { id.setError(RaftError.ESTOP.getNumber()); return true; } Replicator(final ReplicatorOptions replicatorOptions, final RaftOptions raftOptions); @OnlyForTest PriorityQueue<RpcResponse> getPendingResponses(); static ThreadId start(final ReplicatorOptions opts, final RaftOptions raftOptions); static void waitForCaughtUp(final ThreadId id, final long maxMargin, final long dueTime,
                                       final CatchUpClosure done); @Override String toString(); @Override void onError(final ThreadId id, final Object data, final int errorCode); static void sendHeartbeat(final ThreadId id, final RpcResponseClosure<AppendEntriesResponse> closure); static boolean stop(final ThreadId id); static boolean join(final ThreadId id); static long getLastRpcSendTimestamp(final ThreadId id); static boolean transferLeadership(final ThreadId id, final long logIndex); static boolean stopTransferLeadership(final ThreadId id); static boolean sendTimeoutNowAndStop(final ThreadId id, final int timeoutMs); static long getNextIndex(final ThreadId id);  }### Answer:
@Test public void testStop() { final Replicator r = getReplicator(); this.id.unlock(); assertNotNull(r.getHeartbeatTimer()); assertNotNull(r.getRpcInFly()); Replicator.stop(this.id); assertNull(r.id); assertNull(r.getHeartbeatTimer()); assertNull(r.getRpcInFly()); }