async def METHOD_NAME(
    socket_id: SocketID, environ: EnvironDict, app: web.Application
) -> bool:
    """socketio reserved handler for when the fontend connects through socket.io
    Arguments:
        environ -- the WSGI environ, among other contains the original request
    Raises:
        SocketIOConnectionError: HTTPUnauthorized
        SocketIOConnectionError: Unexpected error
    Returns:
        True if socket.io connection accepted
    """
    _logger.debug("client connecting in room %s", f"{socket_id=}")
    try:
        auth_user_handler = auth_user_factory(socket_id)
        user_id = await auth_user_handler(environ["aiohttp.request"])
        await _set_user_in_group_rooms(app, user_id, socket_id)
        _logger.info("Sending set_heartbeat_emit_interval with %s", _EMIT_INTERVAL_S)
        heart_beat_messages: list[SocketMessageDict] = [
            {
                "event_type": SOCKET_IO_HEARTBEAT_EVENT,
                "data": {"interval": _EMIT_INTERVAL_S},
            }
        ]
        await send_messages(
            app,
            user_id,
            heart_beat_messages,
        )
    except web.HTTPUnauthorized as exc:
        msg = "authentification failed"
        raise SocketIOConnectionError(msg) from exc
    except Exception as exc:  # pylint: disable=broad-except
        msg = f"Unexpected error: {exc}"
        raise SocketIOConnectionError(msg) from exc
    return True