dc_link_set_preferred_training_settings
dc_link_set_preferred_training_settings(dc, NULL, NULL, link, false);
dc_link_set_preferred_training_settings(dc, &prefer_link_settings, NULL, link, false);
dc_link_set_preferred_training_settings(dc, NULL, NULL, link, false);
dc_link_set_preferred_training_settings(dc, &prefer_link_settings,
dc_link_set_preferred_training_settings(dc, NULL, NULL, link, false);
dc_link_set_preferred_training_settings(dc, &prefer_link_settings, NULL, link, true);
void dc_link_set_preferred_training_settings(struct dc *dc,