for each control frame.
              </li>
<li class="listitem">
                For each received ping frame, a pong frame will be automatically
                sent.
              </li>
<li class="listitem">
                If a close frame is received, the WebSocket close procedure is performed.
                In this case, when the function returns, the error <a class="link" href="../../boost__beast__websocket__error.html" title="websocket::error"><code class="computeroutput"><span class="identifier">