make bn shareable when frozen

[HoneyryderChuck]

added frozen check on every state change.

[rhenium]

Could you make the part that changes #include <ruby/ractor.h> a separate commit or PR?

[HoneyryderChuck]

@rhenium done. I'll rebase it here once it's merged.

[HoneyryderChuck]

@rhenium done

[rhenium]

#initialize also needs a frozen check.

Could you add a test case to ensure freezing it actually makes it shareable?

[HoneyryderChuck]

#initialize also needs a frozen check.

why and where? 🤔

added a test.

[rhenium]

ossl_bn_initialize() - it doesn't have a rb_check_frozen(self).

[HoneyryderChuck]

gotcha, added. One question though: is it worth it, considering that on intialize, the object isn't expected to be frozen? What would that guard against?

[rhenium]

It's needed because it's callable from Ruby, especially if the object is now expected to be thread safe when frozen. Whether calling #initialize on a frozen object makes sense or not doesn't matter.

[rhenium]

It looks good to me now. Thanks!