private void pushState(Node<K>[] t, int i, int n) {
      TableStack<K> s = spare; // reuse if possible
      if (s != null) {
        spare = s.next;
      } else {
        s = new TableStack<>();
      }
      s.tab = t;
      s.length = n;
      s.index = i;
      s.next = stack;
      stack = s;
    }
Saves traversal state upon encountering a forwarding node.
geode-core/src/main/java/org/apache/geode/internal/concurrent/CompactConcurrentHashSet2.java