code: public static <T> Flux<T> switchOnNext(Publisher<? extends Publisher<? extends T>> mergedPublishers, int prefetch) {
  		return onAssembly(new FluxSwitchMap<>(from(mergedPublishers),
  				identityFunction(),
  				Queues.unbounded(prefetch), prefetch));
  	}
docs: Creates a {@link Flux} that mirrors the most recently emitted {@link Publisher},
  forwarding its data until a new {@link Publisher} comes in in the source.
  <p>
  The resulting {@link Flux} will complete once there are no new {@link Publisher} in
  the source (source has completed) and the last mirrored {@link Publisher} has also
  completed.
  <p>
  <img class="marble" src="doc-files/marbles/switchOnNext.svg" alt="">
  
  @param mergedPublishers The {@link Publisher} of {@link Publisher} to switch on and mirror.
  @param prefetch the inner source request size
  @param <T> the produced type
  
  @return a {@link FluxProcessor} accepting publishers and producing T