docs: public static void register(MetricsRegistry metricsRegistry) {
          checkNotNull(metricsRegistry, "metricsRegistry");
  
          Runtime runtime = Runtime.getRuntime();
          RuntimeMXBean mxBean = ManagementFactory.getRuntimeMXBean();
  
          metricsRegistry.register(runtime, "runtime.freeMemory", MANDATORY, Runtime::freeMemory);
          metricsRegistry.register(runtime, "runtime.totalMemory", MANDATORY, Runtime::totalMemory);
          metricsRegistry.register(runtime, "runtime.maxMemory", MANDATORY, Runtime::maxMemory);
          metricsRegistry.register(runtime, "runtime.usedMemory", MANDATORY,
                  (LongProbeFunction<Runtime>) runtime1 -> runtime1.totalMemory() - runtime1.freeMemory()
          );
          metricsRegistry.register(runtime, "runtime.availableProcessors", MANDATORY, Runtime::availableProcessors);
          metricsRegistry.register(mxBean, "runtime.uptime", MANDATORY, RuntimeMXBean::getUptime);
      }