mergeBy
fun <F, F2 : F, T, T2 : T> SplittingConverter<F, F2, T2, T>.mergeBy(converter: Converter<F2, T2>): Converter<F, T>
Merges this SplittingConverter by delegating to a Converter instance that converts between types F2 and T2. After the merge, a new Converter will be returned which fully converts between types F and T.