They do, and in all of them is an anti-pattern to use raw threads instead of the higher level frameworks like goroutines, java.util.concurrent or TPL/DataFlow.

Go in their typical wisdom, doesn't even support thread local storage.

Additionally, Java and .NET have thrown away their security managers, and guess what is the best practice to regain their features in Java and .NET applications?

Multi-processing with OS IPC.

Sorry, we are discussing shared memory multiprocessing. I'm certainly not advocating unrestricted use of pthread_create, but even more structured way of parallelization still rely on shared memory.

But of course, for security address space separation is pretty much a requirement.

It's not an antipattern to use threads in Rust. Where did you get that idea?