Upstream - the upstream value typeDownstream - the downstream value type@FunctionalInterface public interface FlowableTransformer<Upstream,Downstream>
Flowables.| Modifier and Type | Method and Description | 
|---|---|
@NonNull Publisher<Downstream> | 
apply(@NonNull Flowable<Upstream> upstream)
 | 
@NonNull @NonNull Publisher<Downstream> apply(@NonNull @NonNull Flowable<Upstream> upstream)
Flowable and returns a Publisher with
 optionally different element type.upstream - the upstream Flowable instancePublisher instance