unsafe extern "C" fn stream_renderer_transfer_write_iov(
    handle: u32,
    ctx_id: u32,
    level: c_int,
    stride: u32,
    layer_stride: u32,
    box_: *mut virgl_box,
    offset: u64,
    iovec: *mut iovec,
    iovec_cnt: c_uint
) -> c_int