GObjectToggleNotify

void
(* GToggleNotify) (
  gpointer data,
  GObject* object,
  gboolean is_last_ref
)

A callback function used for notification when the state of a toggle reference changes.

`data`	`gpointer`
	Callback data passed to `g_object_add_toggle_ref()`
	The argument can be `NULL`.
	The data is owned by the caller of the function.
`object`	`GObject`
	The object on which `g_object_add_toggle_ref()` was called.
	The data is owned by the caller of the function.
`is_last_ref`	`gboolean`
	`TRUE` if the toggle reference is now the last reference to the object. `FALSE` if the toggle reference was the last reference and there are now other references.