def shutdown(self):
        err = None
        SocketServer.shutdown(self)
L{hosts.Resolver.lookupIPV6Address} returns a L{Deferred} which fires
dataset/ETHPy150Open bfrog/whizzer/whizzer/server.py/UnixServer.shutdown--crossover with--dataset/ETHPy150Open twisted/twisted/twisted/names/test/test_hosts.py/HostsTests.test_lookupIPV6Address