docs: private boolean isPopulatedMixedValueMap(ResourceFieldSchema schema, int field, Tuple object) {
          if (schema.getType() != DataType.MAP) {
              // Can't be a mixed value map if it's not a map at all.
              return false;
          }
  
          try {
              Object fieldValue = object.get(field);
              Map<?, ?> map = (Map<?, ?>) fieldValue;
              return schema.getSchema() == null && !(map == null || map.isEmpty());
          } catch (ExecException e) {
              throw new EsHadoopIllegalStateException(e);
          }
      }