e call ended.</p>

<pre class="codepre"><code class="code"><span class="keyword">let</span> bytes_length (s : bytes) =
  <span class="constructor">String</span>.length (<span class="constructor">Bytes</span>.unsafe_to_string s)
   </code></pre>
<p>In this use-case, we do not promise that <code class="code">s</code> will never be mutated
   after the call to <code class="code">bytes_length&nbsp;s</code>. The <a href="String.html#VALlength"><code class="code"><span class="constructor">String</span>.length</co