Function fetch_payload 

fn fetch_payload(
    conn: &RustConnection,
) -> Option<(&'static str, Vec<u8>, i32, i32)>

Fetch and convert the current cursor. None on a fetch failure (XFixes returns an error while the cursor is not displayed, e.g. a blanked screen) or an encode failure — mirroring the Wayland gate where only real payloads or an explicit hide go downstream.