Some requirements for the optional parameters:</p><ul><li>Either childList, attributes or characterData must be true.</li><li>If attributeOldValue is true then attributes must also be true.</li><li>If attributeFilter is specified then attributes must be true.</li><li>If characterDataOldValue is true then characterData must be true.</li></ul>
    
    </section>

    <section class="summary source-code" id="source">
      <h2>Source</h2>
      <pre><code class="prettyprint lang-dart">/**
 * Observes the targ