Is it possible to have a map that the feature layer or data from external REST API? I want to have a map that showing feature layer data in real time. However, the ArcGIS server/portal don't have direct access to the backend database. For example, the ArcGIS server/portal is hosted on cloud, and the backend server is hosted on prem. We cannot have directly connect to the database because of the security issue. We have a REST API to expose the data. Any suggestion what to do? We are using ArcGIS Pro to do the development.