Swift - Download remote SQLite file

I'd like to download a remote SQLite database every time my app launches, and have my app use that database.

I don't want to package the database with the app, it needs to be downloaded each time.

I don't want to load a local database from a remote csv file as there are 20k to 50k records and it takes aver a minute to load the csv data into core data.

I simply want a new database to be downloaded each time at start up and the app to use that database.

Can anyone give me examples how to do this - I have spent days searching and I cannot find any examples.

Thanks.