callAPI method
Implementation
Future<TUIValueCallBack<String>> callAPI(String apiName, String jsonParam) {
String userData = Tools.generateUserData();
Completer<TUIValueCallBack<String>> completer = Completer();
_valueCallback2Future<String>(userData, completer);
_engineSDK.Dart_CallAPI(
_engineFFIPointer,
Tools.string2PointerChar(apiName),
Tools.string2PointerChar(jsonParam),
Tools.string2PointerChar(userData));
return completer.future;
}