al review and
        rejected in 2015. It is based on Boost.Asio, and development on the library
        has continued to the present. As of the branch previously linked, it uses
        these message declarations:
      </p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Headers</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Body</span><span class