// template<typename F>
// auto then(F&& func) -> future<decltype(func(*this))>;
-#define BOOST_THREAD_VERSION 4
-#define BOOST_THREAD_PROVIDES_EXECUTORS
+#define BOOST_THREAD_VERSION 5
//#define BOOST_THREAD_USES_LOG
#define BOOST_THREAD_USES_LOG_THREAD_ID
#include <boost/thread/detail/log.hpp>