Update at_socket.c

components/net/at/at_socket/at_socket.c

@@ -791,6 +791,7 @@ int at_sendto(int socket, const void *data, size_t size, int flags, const struct
                 goto __exit;
             }
             sock->state = AT_SOCKET_CONNECT;
+            /* set AT socket receive data callback function */
             at_dev_ops->at_set_event_cb(AT_SOCKET_EVT_RECV, at_recv_notice_cb);
             at_dev_ops->at_set_event_cb(AT_SOCKET_EVT_CLOSED, at_closed_notice_cb);
         }