Value class for ZoneOffset?

[Stephen Colebourne]

I notice from the updated JEP https://openjdk.org/jeps/401 that
ZoneOffset is not intended to become a value class. I assume this is
because of the id and rules cache variables?

It seems to me that ZoneOffset is very much applicable to be a value,
as it's state is fundamentally an int. Performance tests would be
needed, but it might be possible to create the id and rules on the fly
rather than caching them.

thanks
Stephen