Method call

extern/boost/boost/thread/future.hpp:4500–4508

    }

    void call() {
      try {
        this->mark_finished_with_result(this->continuation(boost::move(this->parent)));
      } catch(...) {
        this->mark_exceptional_finish();
      }
      // make sure parent is really cleared to prevent memory "leaks"
      this->parent = F();
    }

    void call(boost::unique_lock<boost::mutex>& lck) {
      try {