fromFutureSource has been deprecated in 2.6.0, use
def fromFutureSource[T, M](future: Future[Graph[SourceShape[T], M]]): Source[T, Future[M]]
fromFutureSource has been deprecated in 2.6.0, use futureSource instead.
Streams the elements of the given future source once it successfully completes. If the future fails the stream is failed.
emits the next value from the future source, once it has completed
completes after the future source completes