code: public alluxio.grpc.MetricValue getMetricsOrDefault(
        java.lang.String key,
        alluxio.grpc.MetricValue defaultValue) {
      if (key == null) { throw new java.lang.NullPointerException(); }
      java.util.Map<java.lang.String, alluxio.grpc.MetricValue> map =
          internalGetMetrics().getMap();
      return map.containsKey(key) ? map.get(key) : defaultValue;
    }
docs: <code>map&lt;string, .alluxio.grpc.meta.MetricValue&gt; metrics = 1;</code>