ring</code> or
   <code class="code">unsafe_to_string</code> whenever applicable.</p>

<p>2. Temporarily giving ownership of a byte sequence to a function
   that expects a uniquely owned string and returns ownership back, so
   that we can mutate the sequence again after the call ended.</p>

<pre class="codepre"><span class="keyword">let</span> bytes_length (s : bytes) =
  String.length (Bytes.unsafe_to_string s)
   </pre>
<p>In this use-case, we do not promise that <code class="code">s</code> will never b