partitionEithers method
Partition into 2 Lists, the first containing Left the values and the second containing the Right values.
Implementation
List<List<dynamic>> partitionEithers() => fold(
[<A>[], <B>[]],
(r, either) {
either.visit(
left: (r.first as List<A>).add,
right: (r.last as List<B>).add,
);
return r;
},
);