map2<C, D> method
Change the return type of this IOEither based on its value of type R
and the
value of type C
of another IOEither.
Implementation
@override
IOEither<L, D> map2<C, D>(
covariant IOEither<L, C> m1, D Function(R b, C c) f) =>
flatMap((b) => m1.map((c) => f(b, c)));