Queries the current state of the named action within @action_group.
If the action is not stateful then %NULL will be returned. If the
action is stateful then the type of the return value is the type
given by g_action_group_get_action_state_type().
The return value (if non-%NULL) should be freed with
g_variant_unref() when it is no longer required.
Queries the current state of the named action within @action_group.
If the action is not stateful then %NULL will be returned. If the action is stateful then the type of the return value is the type given by g_action_group_get_action_state_type().
The return value (if non-%NULL) should be freed with g_variant_unref() when it is no longer required.