Arrow Meta brings Unions, which are similar to Eit...

# arrow

[CLOVIS]

Arrow Meta brings Unions, which are similar to Either but not quite the same (Either has map etc on its right side, Unions can be combined). To model error handling, when should we use Either and when should we use Union?
To me Either makes a lot of sense because `map`and fx blocks make short-circuiting in case of errors easy to read, but at the same time combining Unions can be convenient...