Function grn_array_push 

pub unsafe extern "C" fn grn_array_push(
    ctx: *mut grn_ctx,
    array: *mut grn_array,
    func: Option<unsafe extern "C" fn(ctx: *mut grn_ctx, array: *mut grn_array, id: grn_id, func_arg: *mut c_void)>,
    func_arg: *mut c_void,
) -> grn_id