.</p>
<p>Acts on the substring from <code>start</code> to <code>end</code>. If <code>end</code> is omitted, it
defaults ot the end of the string.</p>
<p>Some examples of IPv6 addresses:</p><ul><li>::1</li><li>FEDC:BA98:7654:3210:FEDC:BA98:7654:3210</li><li>3ffe:2a00ðŸ’¯7031::1</li><li>::FFFF:129.144.52.38</li><li>2010:836B:4179::836B:4179</li></ul>
    </section>
    
    <section class="summary source-code" id="source">
      <h2><span>Implementation</span></h2>
      <pre class="language-dart"><code 