[$] MemHive: sharing immutable data between Python subinterpreters

Immutable data makes concurrent access easier, since iteliminates the data-race conditions that can plague multithreaded programs. AtPyCon2024, Yury Selivanovintroduced an early-stage project called MemHive, which uses Pythonsubinterpreters and immutable data toovercome the problems of thread serialization that are caused by thelanguage's Global Interpreter Lock (GIL). Recent developments in the Python world have openedup different strategies for avoiding the longstanding problems with theGIL.