docs: static JmxConfig from(Config config) {
      try {
        ObjectName query = new ObjectName(config.getString("query"));
        List<JmxMeasurementConfig> ms = new ArrayList<>();
        for (Config cfg : config.getConfigList("measurements")) {
          ms.add(JmxMeasurementConfig.from(cfg));
        }
        return new JmxConfig(query, ms);
      } catch (Exception e) {
        throw new IllegalArgumentException("invalid mapping config", e);
      }
    }