special">&amp;</span> <span class="identifier">error</span><span class="special">,</span> <span class="comment">// Result of operation.</span>

  <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">bytes_transferred</span>           <span class="comment">// Number of bytes written from the</span>
                                          <span class="comment">// buffers. If an error occurred,</span>
                               