I have written an application for macOS that is dealing with 50-100 network requests per second and the memory is constantly growing (reaching 1gb per day). The first version was in Swift, so I believed it was a Swift related issue and reported it here https://bugs.swift.org/browse/SR-14194. Then I decided to rewrite my application in Rust and surprisingly had the same memory issue. Same code runs fine on Linux.
Example in Rust:
https://gist.github.com/telcy/b1c3a444def65dd0f1d109b6a98db0f1
Usually I try to find the issue at my end, but this seems to be out of my control. It is a bit mind boggling for me how a crucial part of an operating system leaks memory without anyone noticing.
I hope this gets some attention (and discussion) as this would mean most applications on macOS with network requests do leak memory to some extent.
The best you can do is write the most concise example in an officially-supported language and file a Feedback.
It took about a year and a half or sofor both of my NSURL (one was pretty severe) leaks to be fixed, but this was years ago. Good luck.