Additionally, until very recently, there was no (practical) way to reach the performance potential of manual memory management in pure Swift: all heap management was done via Automatic Reference Counting (ARC). A series of "ownership" features have been getting integrated into the most recent versions of the language that let you avoid that runtime cost while retaining memory safety (at the expense of more complex code — the vast majority of code should still use ARC). That makes Swift much more suitable for lots of "systems programming" than it was just a few months ago. https://www.swift.org/blog/swift-5.9-released/#ownership
