@Override
  public Iterator<E> iterator() {
    return new Itr();
  }
Returns an iterator over the elements in this queue in proper sequence. The returned
{@code Iterator} is a "weakly consistent" iterator that will never throw
{@link java.util.ConcurrentModificationException ConcurrentModificationException}, and
guarantees to traverse elements as they existed upon construction of the iterator, and may (but
is not guaranteed to) reflect any modifications subsequent to construction.

@return an iterator over the elements in this queue in proper sequence
geode-core/src/main/java/org/apache/geode/internal/cache/ForceableLinkedBlockingQueue.java