[$] Deterministic testing for multithreaded Python

Python's support for multithreaded programs has improved considerably overthe last few years with the advent of the "free-threaded" version of the language. Buttesting multithreaded programs is notoriously difficult, because theunderlying host system determines the thread-execution ordering, which addsan element of non-determinism. At PyCon US, Larry Hastings gave a talk (YouTube video)about his blanket project,which is meant to provide mechanisms for deterministic testing ofmultithreaded Python code.