Function lumen_node_valid 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn lumen_node_valid(
    node: LumenNode,
    out: *mut c_int,
) -> LumenStatus

Whether node is present in the current snapshot (1) or not (0), written to *out. The snapshot rebuilds each tick, so a despawned node reads 0. Thread-safe.