Replace "use threads;" with something else as it is "discouraged"

[Happy86]

Hi,

https://perldoc.perl.org/threads#WARNING says:

The "interpreter-based threads" provided by Perl are not the fast,
lightweight system for multitasking that one might expect or hope for.
Threads are implemented in a way that makes them easy to misuse.
Few people know how to use them correctly or will be able to provide help.

The use of interpreter-based threads in perl is officially discouraged.

And https://perldoc.perl.org/perlpolicy#discouraged says:

From time to time, we may mark language constructs and features which
we consider to have been mistakes as discouraged.
Discouraged features aren't currently candidates for removal, but we may
later deprecate them if they're found to stand in the way of a significant
improvement to the Perl core.

Therefore use threads will probably be deprecated and removed in the future.

Though I have not yet looked into it in which "future-proof" way this can be remedied.

Personally I had good experiences with Parallel::Loops.

The usual search on Stackoverflow/... yields:

• https://metacpan.org/pod/Parallel::ForkManager
• https://metacpan.org/pod/IO::Async::Function
• https://metacpan.org/pod/Thread::Queue (still seems to use threads; directly in the synopsis 0.o)

Of course it could be that interpreter-based threads will never be deprecated (or just before the heat death of the universe in which case this issue is probably mute and can be closed) but I just cannot imagine the Perl core developers just write such a warning for fun...

Best regards,
Andreas