append(buf, "percent", () -> mem.getHeapUsedPercent());
        buf.append("},");
        buf.append("\"non_heap\":{");
        append(buf, "used", () -> mem.getNonHeapUsed().getBytes()).append(',');
        append(buf, "committed", () -> mem.getNonHeapCommitted().getBytes());
        buf.append('}');
        buf.append("},");