The moment you turn on garbage collection in Dlang, you've introduced stop the world pauses to all your Dlang threads.
If you were to implement a Rust GC, then Rust can guarantee that references haven't escaped the current thread, which means there is no stop the world pause anymore, only the current thread gets paused, which is acceptable.
If you were to implement a Rust GC, then Rust can guarantee that references haven't escaped the current thread, which means there is no stop the world pause anymore, only the current thread gets paused, which is acceptable.