ush a <code>&amp;str</code> onto the end of a <code>String</code> without
checking anything dynamically, since the existing <code>String</code> and <code>&amp;str</code> are
statically guaranteed to be in utf-8.</p></li>
<li><p>Some <em>producers</em> of a <code>String</code> must perform dynamic checks. For example, the
<code>from_utf8</code> function attempts to convert a <code>Vec&lt;u8&gt;</code> into a <code>String</code>, but
dynamically checks that the contents are utf-8.</p></li>
</ul>

<h3 id='prov