relatedFieldJson function
This is more complicated because previously we were needing to pull the field json out into a separate root
Implementation
RelatedBuilder relatedFieldJson(String fieldName, dynamic json) {
return (JsonObject map) {
if (json == null ||
(json is Map && json.isEmpty) ||
(json is Iterable && json.isEmpty)) {
return;
}
map[fieldName] = json;
};
}