andThen<U, F> method
Similar to map Except you must return a new Result.
This is useful for when you need to do a subsequent computation using the
inner T value, but that computation might fail.
Additionally, andThen is really useful as a tool to flatten a
Result<Result<A, E2>, E1> into a Result<A, E2> (see example below).
@param f The function to apply to the current value
Implementation
@override
Result<U, F> andThen<U, F>(Result<U, F> Function(T t) f) => f(this.value);