/guava/android/guava/src/com/google/common/collect/TreeTraverser.java
stack.addLast( expand( child) ) ; T child = top.childIterator.next( ) ;
T child = top.childIterator.next ( ) ; stack.addLast ( expand ( child ) ) ;
@Override @CheckForNull protected T computeNext() { while (!stack.isEmpty()) { PostOrderNode<T> top = stack.getLast(); if (top.childIterator.hasNext()) { <extra_id_0> } else { stack.removeLast(); return top.root; } } return endOfData();