ReactorCheckBlanks.kt

        val blank = Function<Map.Entry<Int, LongWrapper>, Flux<Long>> { entry ->
            Flux.just(max(0L, entry.value.get() - scrabbleAvailableLetters[entry.key - 'a'.toInt()]))
        }

        val nBlanks = Function<String, Flux<Long>> { word ->
            Flux.from(histoOfLetters.apply(word)
                .flatMap<Map.Entry<Int, LongWrapper>> { map -> 
                                                       Flux.fromIterable<Map.Entry<Int, LongWrapper>>(
                                                               Iterable { map.entries.iterator() }) }
                .flatMap(blank)
                .reduce { a, b -> sum(a, b) })
        }

        val checkBlanks = Function<String, Flux<Boolean>> { word ->
            nBlanks.apply(word)
                .flatMap { l -> Flux.just(l <= 2L) }
        }


        val score2 = Function<String, Flux<Int>> { word ->
            Flux.from(histoOfLetters.apply(word)
                .flatMap<Map.Entry<Int, LongWrapper>> { map -> 
                                                       Flux.fromIterable<Map.Entry<Int, LongWrapper>>(
                                                               Iterable { map.entries.iterator() }) }
                .flatMap(letterScore)
                .reduce { a, b -> Integer.sum(a, b) })

        }