   uniquely-owned again.</p>

<p><code class="code">unsafe_to_string&nbsp;s</code> can only be used when the caller owns the byte
   sequence <code class="code">s</code> -- either uniquely or as shared immutable data. The
   caller gives up ownership of <code class="code">s</code>, and gains ownership of the
   returned string.</p>

<p>There are two valid use-cases that respect this ownership
   discipline:</p>

<p>1. Creating a string by initializing and mutating a byte sequence
   that is never changed af