code: public void startUpdate(String targetId) throws IOException {
          startChangesIfNecessary();
          inUpdate = true;
          ResponseWriter writer = getWrapped();
          writer.startElement("update", null);
          writer.writeAttribute("id", targetId, null);
          writer.startCDATA();
      }
docs: <p class="changed_added_2_0">Write the start of an update operation.</p>
  
  @param targetId ID of the node to be updated
  @throws IOException if an input/output error occurs
  @since 2.0