Specialized Partition for `IEnumerable<Either<Left, Right>>`

[Mafii]

That would be really useful, as:

var results = enumerable.Select(MethodReturningEither).Materialize(); // Materialize only needed for select many's after
var rights = results.SelectMany(e => e.RightOrNone().ToEnumerable()); // <- just really verbose for a partition
var lefts = results.SelectMany(e => e.LeftOrNone().ToEnumerable());

expected API:

var (lefts, rights) = enumerable.Select(MethodReturningEither).Partition()

[bash]

It already is