Function lumen_node_spawn 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn lumen_node_spawn(
    tag: *const c_char,
    out: *mut LumenNode,
) -> LumenStatus

Create a fresh detached element with markup tag tag, writing its handle to *out. The handle is valid for the rest of the tick; attach it with lumen_node_append / lumen_node_set_parent. Thread-safe.