lass="features">override</div>
    </section>
    <section class="desc markdown">
      <p>Returns <code>this</code> as a <a href="dart-convert/ClosableStringSink-class.html">ClosableStringSink</a>.</p>
<p>If used, this method must be the first and only call to <code>this</code>. It
invalidates <code>this</code>. All further operations must be performed on the result.</p>
    </section>
    
    <section class="summary source-code" id="source">
      <h2><span>Implementation</span></h2>
      <pre class="la