an><span class="special">&gt;</span> <span class="special">&gt;;</span>

  <span class="keyword">mutable</span> <span class="identifier">headers_container_type</span> <span class="identifier">headers_</span><span class="special">;</span>
  <span class="keyword">mutable</span> <span class="identifier">string_type</span> <span class="identifier">body_</span><span class="special">;</span>
  <span class="keyword">mutable</span> <span class="identifier">string_type</span> <span class="identifier">source_</span><