Migrate from LocalDataSource to ServerDataSource

I'm having difficulties trying to migrate to ServerDataSource.

We are do all our backend call vie AuthService like [this one](https://medium.com/@ryanchenkie_40935/angular-authentication-using-the-http-client-and-http-interceptors-2f9d1540eb8) which returns https Promis. The AuthService is called but custom Service which encapsulates our business logic and also returns promise. The custom service is called by a component and uses LocalDataSource .load method to set the data to the grid.

I would like to take advantage of the sorting and the pagination of the ServerDataSource but not doing the backend request thru the ServerDataSource .