"../../dart-core/String-class.html">String</a></span>&gt;</span></span> <span class="parameter-name">supportedProtocols</span>}</span></li>
</ol>)
      
    </section>
    <section class="desc markdown">
      <p>Takes an already connected <code>socket</code> and starts server side TLS
handshake to make the communication secure. When the returned
future completes the <a href="../../dart-io/RawSecureSocket-class.html">RawSecureSocket</a> has completed the TLS
handshake. Using this function requires that the