		void start() {
			assert(thr == NULL);
			thr = new oxt::thread(boost::bind(&BackgroundIOCapturer::capture, this),
				"Background I/O capturer", 64 * 1024);
		}
		void start() {
			assert(thr == NULL);
			thr = new oxt::thread(boost::bind(&BackgroundIOCapturer::capture, this),
				"Background I/O capturer", 64 * 1024);
		}