Pattern Matching on Discriminated Unions Without `_tag` Discriminator
I am trying to use the pattern matching functionality on a discriminated union type. Using 
Match.value(...) on the sub-field works, but it doesn't typecast the object. I see Match.tag(...), but that says it only works if the discriminator is _tag. I have a lot of discriminated unions that do not use _tag and I'd like to avoid re-working them all if I can. Hoping someone here has suggestions 
