There are three ways of sharing data across threads.
One is by sharing the data with the thread when it is spawned via a closure. Spawning will fence. No problem there.
The second is to use a good 'ol Sender/Receiver channel pair. These are effectively a shared ring buffer that you can push to and pop from. They also have a fence somewhere.
Finally, you can stick your data into a mutex shared between threads (and let the other thread wait and read it). This will IIRC fence, or do something equivalent.
You can of course build your own ways to do this, but they will need unsafe code to be built (the three APIs above are also built with unsafe code). It is up to you to ensure you handle the fences right when doing this.
The responsibility here is on the publishing mechanism. Most folks use one of the three ways above using primitives from the stdlib depending on the use case.
