code: public static void initBackendFactory(Timer timer) throws IOException {
  		RrdNioBackend.setFileSyncTimer(timer);
  
  		try {
  			if (!RrdBackendFactory.getDefaultFactory().getFactoryName()
  					.equals(RrdNioBackendFactory.FACTORY_NAME)) {
  				RrdBackendFactory.registerAndSetAsDefaultFactory(new RrdNioBackendFactory());
  			}
  		} catch (final RrdException e) {
  			throw createIOException(e);
  		}
  	}
docs: JavaMelody uses a custom RrdNioBackendFactory,
  in order to use its own and cancelable file sync timer.
  @param timer Timer
  @throws IOException e