Definitely. Have a look at type ristrettoMap, you’ll see the sync primitives embedded in that structure. And of course the accessors to that type have mutex operations.
I doubt that. Definitely not part of the design… you could try adding that with IPCs or Google’s groupcache… PRs always welcome! But seriously, at that point using a DB (say, Dgraph for instance) is the next architectural boundary you might consider.