meshlink_channel_t *channel2 = meshlink_channel_open(a, nb, 7, a_receive_cb, NULL, 0);
assert(channel2);
meshlink_set_channel_poll_cb(a, channel2, poll_cb2);
meshlink_channel_t *channel2 = meshlink_channel_open(a, nb, 7, a_receive_cb, NULL, 0);
assert(channel2);
meshlink_set_channel_poll_cb(a, channel2, poll_cb2);