A lot of people still don't have Perl 5.16. 5.10 is pretty safe,
though. You are using use 5.016 simply to enable the state
keyword, but that was available as of 5.10, so you could use 5.010.
However, rather than enabling all of the features of Perl 5.10, it's
much safer to just enable what you need, which would mean simply
use feature 'state';.
A lot of people still don't have Perl 5.16. 5.10 is pretty safe, though. You are using
use 5.016simply to enable thestatekeyword, but that was available as of 5.10, so you coulduse 5.010. However, rather than enabling all of the features of Perl 5.10, it's much safer to just enable what you need, which would mean simplyuse feature 'state';.