code: public void marshall(GetRelationalDatabaseMetricDataRequest getRelationalDatabaseMetricDataRequest, ProtocolMarshaller protocolMarshaller) {
  
          if (getRelationalDatabaseMetricDataRequest == null) {
              throw new SdkClientException("Invalid argument passed to marshall(...)");
          }
  
          try {
              protocolMarshaller.marshall(getRelationalDatabaseMetricDataRequest.getRelationalDatabaseName(), RELATIONALDATABASENAME_BINDING);
              protocolMarshaller.marshall(getRelationalDatabaseMetricDataRequest.getMetricName(), METRICNAME_BINDING);
              protocolMarshaller.marshall(getRelationalDatabaseMetricDataRequest.getPeriod(), PERIOD_BINDING);
              protocolMarshaller.marshall(getRelationalDatabaseMetricDataRequest.getStartTime(), STARTTIME_BINDING);
              protocolMarshaller.marshall(getRelationalDatabaseMetricDataRequest.getEndTime(), ENDTIME_BINDING);
              protocolMarshaller.marshall(getRelationalDatabaseMetricDataRequest.getUnit(), UNIT_BINDING);
              protocolMarshaller.marshall(getRelationalDatabaseMetricDataRequest.getStatistics(), STATISTICS_BINDING);
          } catch (Exception e) {
              throw new SdkClientException("Unable to marshall request to JSON: " + e.getMessage(), e);
          }
      }
docs: Marshall the given parameter object.