@Override
  public N next() {
    if (!hasNext()) {
      throw new NoSuchElementException();
    }
    N result = nextMatchedNode;
    nextMatchedNode = null;
    return result;
  }
TraverserIterator for traversing device node. The iterator returns the filtered child nodes in
the mtree and the child nodes in the template.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/mem/mnode/iterator/AbstractTraverserIterator.java