Common interface for objects (containers) that can have multiple contents (sub-objects).
APIs in this interface deal with containers of multiple sub-objects, not with individual parts.
Returns the number of contained sub-objects.
int efl_content_count(Eo *obj);
Begin iterating over this object's contents.
Eina_Iterator *efl_content_iterate(Eo *obj);
Sent after a new sub-object was added.
Sent after a sub-object was removed, before unref.