/guava/android/guava/src/com/google/common/graph/Traverser.java
horizon.add ( startNodes ) ;
} }; } final Iterator<N> postOrder(Iterator<? extends N> startNodes) { Deque<N> ancestorStack = new ArrayDeque<>(); Deque<Iterator<? extends N>> horizon = new ArrayDeque<>(); <extra_id_0> return new AbstractIterator<N>() { @Override @CheckForNull protected N computeNext() { for (N next = visitNext(horizon); next != null; next = visitNext(horizon)) { Iterator<? extends N> successors = successorFunction.successors(next).iterator();