'Re-listening with the same L{DatagramProtocol} re-invokes the
C{startProtocol} callback.'

def test_rebind(self):

    server = Server()
    d = server.startedDeferred = defer.Deferred()
    p = reactor.listenUDP(0, server, interface='127.0.0.1')
    def cbStarted(ignored, port):
        return port.stopListening()
    def cbStopped(ignored):
        d = server.startedDeferred = defer.Deferred()
        p = reactor.listenUDP(0, server, interface='127.0.0.1')
        return d.addCallback(cbStarted, p)
    return d.addCallback(cbStarted, p)
