final Threads threads = jvmStats.getThreads();
        buf.append("\"threads\":{");
        append(buf, "count", () -> threads.getCount()).append(',');
        append(buf, "peak", () -> threads.getPeakCount());
        buf.append("},");
        final Classes classes = jvmStats.getClasses();
        buf.append("\"classes\":{");
        append(buf, "loaded", () -> classes.getLoadedClassCount()).append(',');