default Function4 andThen()

in src/main/java/com/spotify/futures/Function4.java [69:72]

• 4 lines of code
• 1 McCabe index (conditional complexity)

  default <V> Function4<A, B, C, D, V> andThen(Function<? super R, ? extends V> after) {
    Objects.requireNonNull(after);
    return (A a, B b, C c, D d) -> after.apply(apply(a, b, c, d));
  }