code: private static Map<String, Node> getFields(Node node) {
          Map<String, Node> result = new HashMap<>();
          Iterator<KeyValue> fields = node.fields();
          while (fields.hasNext()) {
              KeyValue field = fields.next();
              result.put(field.getKey(), field.getValue());
          }
          return Collections.unmodifiableMap(result);
      }
docs: Returns children of an ObjectNode.
  
  @param node
  @return