[semidet]py_gil_owner(-Thread)True when the Python GIL is owned by Thread. Note that,
unless
Thread is the calling thread, this merely samples the current
state and may thus no longer be true when the predicate succeeds. This
predicate is intended to help diagnose deadlock problems.
Note that this predicate returns the Prolog threads that locked the
GIL. It is however possible that Python releases the GIL, for example if
it performs a blocking call. In this scenario, some other thread or no
thread may hold the gil.
