();
   virtual void <strong>sent_not_interested</strong> ();
   virtual void <strong>sent_payload</strong> (int <em>/* bytes */</em>);
   virtual bool <strong>can_disconnect</strong> (error_code const&amp; <em>/*ec*/</em>);
   virtual bool <strong>on_extended</strong> (int <em>/*length*/</em>, int <em>/*msg*/</em>,
      span&lt;char const&gt; <em>/*body*/</em>);
   virtual bool <strong>on_unknown_message</strong> (int <em>/*length*/</em>, int <em>/*msg*/</em>,
      span&lt;char const&gt; <em>/*body*/</em>