Creating a closure and scheduling it on a queue seems like a pretty heavyweight way to ensure exclusive access (see https://www.cocoawithlove.com/blog/2016/06/0

Creating a closure and scheduling it on a queue seems like a pretty heavyweight way to ensure exclusive access (see https://www.cocoawithlove.com/blog/2016/06/02/threads-and-mutexes.html#mutexes-and-closure-capture-pitfalls https://www.cocoawithlove.com/blog/2016/06/02/threads-and-mu... for more). EDIT: aren't you the one that wrote this article ? :))