Disconnect all the clients NOW, regardless if they process a request
        at the moment.

def disconnectAll(self):
        '''
        Disconnect all the clients NOW, regardless if they process a request
        at the moment.
        '''
        if not self.connections:
            return defer.succeed(None)
        result = self._notifier.wait('idle')
        for connection in self.connections:
            connection.transport.loseConnection()
        return result