I have 3 functions to run in series , all have api calls to make but 2nd function has multiple api call and after all api of 2nd function is executed and saved to Core Data then 3rd function is called . Then after 3rd function again all functions are called I want all this to work when app in background . i am currently using begin background task and end background task

I need help with uploading a lots of images in background using url session and saving the session to resume later. Any help would be appreciated. Thanks