As far as I know, the new concurrency features can be adopted gradually which would make it very simple for developers to transition from the current completion

As far as I know, the new concurrency features can be adopted gradually which would make it very simple for developers to transition from the current completionHandler-based model to the new async/await-based model. Every Obj-C UIKit method with such a completionHandler parameter would from now on be available in two ways from Swift: 1. as usual, with completionHandler 2. new, without completionHandler, marked as ‚async‘ and returning the input types of the completionHandler