Add Bifunctor instance for ReqResult

[odr]

No description provided.

[imalsogreg]

Thanks!

[imalsogreg]

BTW, just curious, when would you want to call first on the tag?

[odr]

BTW, just curious, when would you want to call first on the tag?

I need to check that result has the same tag as current value of param. So I use tag. But I want to isolate it from caller. So I've made function that set tag, check tag and drop tag (set to Unit).