
                              <td>
                                <code>
                                <em>diffingKey</em>
                                </code>
                              </td>
                              <td>
                                <div>
                                  <p>a <code>String</code> key unique to this section that is used to diff sections
automatically. Pass in <code>nil</code> if you are not using automatic diffing on this collection.</p>
                 