andThen<B> method
Implementation
Stackless<B> andThen<B>(Stackless<B> Function(A) f) => switch (this) {
// 1
AndThen<B, A>(sub: Stackless<B> a, k: Stackless<A> Function(B) g) //
=>
AndThen<B, B>(a, (B x) => AndThen<A, B>(g(x), f)),
// 2
Stackless<A> x => AndThen(x, f),
};