The key which corresponds to the target data within a file.
Some file types can contain multiple data streams which are indexed by a key. Use this property for such cases (See for example Efl.Ui.Image or Efl.Ui.Layout).
You must not modify the strings on the returned pointers.
Since 1.22
@property key { get {} set {} values { key: string; } }
const char *efl_file_key_get(const Eo *obj); void efl_file_key_set(Eo *obj, const char *key);