foldAsync

Just like fold but receives a function that results in a Future CompletionStage to the next value.

Signature

def foldAsync[T](zero: T)(f: (T, Out) => Future[T]): Repr[T]

Just like fold but receives a function that results in a Future CompletionStage to the next value.

Note that the zero value must be immutable.

emits when upstream completes and the last Future CompletionStage is resolved

backpressures when downstream backpressures

completes when upstream completes and the last Future CompletionStage is resolved