Send an event to all the client listening for notifications

        :param action: Action name
        :param event: Event to send
        :param kwargs: Add this meta to the notification (project_id for example)

def emit(self, action, event, **kwargs):
        """
        Send an event to all the client listening for notifications

        :param action: Action name
        :param event: Event to send
        :param kwargs: Add this meta to the notification (project_id for example)
        """
        for listener in self._listeners:
            listener.put_nowait((action, event, kwargs))