private Optional<V> insertDual(final TrieMap<K, V> ct, final CNode<K, V> cn, final int pos, final SNode<K, V> sn,
final K k, final V v, final int hc, final int lev) {
final CNode<K, V> rn = (cn.gen == gen) ? cn : cn.renewed(gen, ct);
private Optional<V> insertDual(final TrieMap<K, V> ct, final CNode<K, V> cn, final int pos, final SNode<K, V> sn,
final K k, final V v, final int hc, final int lev) {
final CNode<K, V> rn = (cn.gen == gen) ? cn : cn.renewed(gen, ct);