code: public int insert(int element, Envelope2D boundingBox, int hintIndex) {
  		return m_impl.insert(element, boundingBox, hintIndex);
  	}
docs: Inserts the element and bounding_box into the QuadTree at the given
  quad_handle. Note that a copy will me made of the input bounding_box.
  Note that this will invalidate any active iterator on the QuadTree.
  Returns an Element_handle corresponding to the element and bounding_box.
  \param element The element of the Geometry to be inserted.
  \param bounding_box The bounding_box of the Geometry to be inserted.
  \param hint_index A handle used as a hint where to place the element. This can
  be a handle obtained from a previous insertion and is useful on data
  having strong locality such as segments of a Polygon.