/span>
    <span class="keyword">void</span> <span class="identifier">set_progress_handler</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">progress_handler</span> <span class="special">&amp;</span><span class="identifier">handler</span><span class="special">);</span>

<span class="keyword">private</span><span class="special">:</span>
    <span class="keyword">friend</span> <span class="keyword">class</span> <span class="identifier">http</span><span class="spec