add override and a TODO

include/libtorrent/kademlia/put_data.hpp

@@ -58,7 +58,7 @@ struct put_data: traversal_algorithm
 	put_data(node& node, put_callback const& callback);
 
 	virtual char const* name() const;
-	virtual void start();
+	virtual void start() TORRENT_OVERRIDE;
 
 	void set_data(item const& data) { m_data = data; }
 

src/kademlia/put_data.cpp

@@ -93,6 +93,9 @@ bool put_data::invoke(observer_ptr o)
 		m_invoke_count = -1;
 		return false;
 	}
+
+	// TODO: what if o is not an isntance of put_data_observer? This need to be
+	// redesigned for better type saftey.
 	put_data_observer* po = static_cast<put_data_observer*>(o.get());
 
 	entry e;