pub unsafe extern "C" fn g_dbus_connection_signal_subscribe(
connection: *mut GDBusConnection,
sender: *const c_char,
interface_name: *const c_char,
member: *const c_char,
object_path: *const c_char,
arg0: *const c_char,
flags: GDBusSignalFlags,
callback: GDBusSignalCallback,
user_data: gpointer,
user_data_free_func: GDestroyNotify,
) -> c_uint