ef="concepts/BodyReader.html" title="BodyReader"><span class="emphasis"><em>BodyReader</em></span></a>
          and <a class="link" href="concepts/BodyWriter.html" title="BodyWriter"><span class="emphasis"><em>BodyWriter</em></span></a>
          concept constructor requirements have changed. They now require the header
          and body elements to be passed as distinct <a class="link" href="ref/boost__beast__http__header.html" title="http::header"><code class="computeroutput"><span class="identifier">ht