@Override
        public boolean hasNext() {
            if (nextIndex >= items.length) {
                return false;
            }
            if (items[nextIndex] == null) {
                return false;
            }
            return true;
        }
<p>Returns an iterator over the items in this list. As opposed to <code>CopyOnWriteArrayList</code>, this iterator
may see items added to the <code>ThreadRobustList</code> even if they occur <em>after</em> a call to this method.</p>
<p>The returned iterator does not support <code>remove()</code>.</p>

@return an iterator over this list
vespajlib/src/main/java/com/yahoo/yolean/concurrent/ThreadRobustList.java