pub unsafe extern "C" fn mlx_custom_vjp(
res: *mut mlx_closure,
fun: mlx_closure,
fun_vjp: mlx_closure_custom,
) -> c_intpub unsafe extern "C" fn mlx_custom_vjp(
res: *mut mlx_closure,
fun: mlx_closure,
fun_vjp: mlx_closure_custom,
) -> c_int