maybe
Materialize a Promise[Option[T]] that if completed with a Some[T] will emit that T and then complete the stream, or if completed with None complete the stream right away.
Description
Materialize a Promise[Option[T]] that if completed with a Some[T] will emit that T and then complete the stream, or if completed with None complete the stream right away.
emits when the returned promise is completed with some value
completes after emitting some value, or directly if the promise is completed with no value