I thought Stream.expand(f) is flatMap. i.e. From docs: "Creates a new stream from this stream that converts each element into zero or more events." Stream.tak

I thought Stream.expand(f) is flatMap. i.e. From docs: "Creates a new stream from this stream that converts each element into zero or more events." Stream.takeWhile(f) is takeUntil with the return value of the f argument negated. But sure, you can always add more features to a core library, the difficult decision is when to stop, and leave the rest to libraries.