fun <T, R> ParallelFlow<T>.reduce(seed: suspend () -> R, combine: suspend (R, T) -> R): ParallelFlow<R>
Reduces the source items into a single value on each rail and emits those.
@FlowPreview fun <T> ParallelFlow<T>.reduce(combine: suspend (T, T) -> T): Flow<T>
Reduce the values within the parallel rails and then reduce the rails to a single result value.