reactor-core/src/main/java/reactor/core/publisher/ParallelFlux.java
public final Flux<T> ordered(Comparator<? super T> comparator) {
		return ordered(comparator, Queues.SMALL_BUFFER_SIZE);
	}
public final Flux<T> ordered(Comparator<? super T> comparator) {
		return ordered(comparator, Queues.SMALL_BUFFER_SIZE);
	}
Merges the values from each 'rail', but choose which one to merge by way of a
provided {@link Comparator}, picking the smallest of all rails. The result is
exposed back as a {@link Flux}.
<p>
This version uses a default prefetch of {@link Queues#SMALL_BUFFER_SIZE}.

@param comparator the comparator to choose the smallest value available from all rails
@return the new Flux instance

@see ParallelFlux#ordered(Comparator, int)