Cannot derive from AdwToast
When one has a button on the AdwToast, it would make sense to remember state data for the "button-clicked" signal on the object. I thought I'll derive from the AdwToast object and will add properties I'd use, but it turned out it's a final type, which means no way to derive from it.
There are workarounds to achieve something similar (I use g_object_set_data_full), but it's not that elegant as having the object properly hold the data I want to have stored with it and use when the button is clicked.
I do not know whether anything like:
void adw_toast_set_data (AdwToast *self, gpointer data, GDestroyNotify destroy);
gpointer adw_toast_get_data (AdwToast *self);
would be acceptable/make any sense here.