reactor-core/src/main/java/reactor/core/publisher/Flux.java
public final ParallelFlux<T> parallel(int parallelism, int prefetch) {
		return ParallelFlux.from(this,
				parallelism,
				prefetch,
				Queues.get(prefetch));
	}
public final ParallelFlux<T> parallel(int parallelism, int prefetch) {
		return ParallelFlux.from(this,
				parallelism,
				prefetch,
				Queues.get(prefetch));
	}
public final ParallelFlux < T > parallel ( int parallelism , int prefetch ) { return ParallelFlux . from ( this , parallelism , prefetch , Queues . get ( prefetch ) ) ; }
Prepare this {@link Flux} by dividing data on a number of 'rails' matching the
provided {@code parallelism} parameter, in a round-robin fashion and using a
custom prefetch amount and queue for dealing with the source {@link Flux}'s values.
Note that to actually perform the work in parallel, you should call
{@link ParallelFlux#runOn(Scheduler)} afterward.

<p>
<img class="marble" src="doc-files/marbles/parallel.svg" alt="">

@param parallelism the number of parallel rails
@param prefetch the number of values to prefetch from the source

@return a new {@link ParallelFlux} instance
Prepare this { @link Flux } by dividing data on a number of rails matching the provided { @code parallelism } parameter in a round - robin fashion and using a custom prefetch amount and queue for dealing with the source { @link Flux } s values . Note that to actually perform the work in parallel you should call { @link ParallelFlux#runOn ( Scheduler ) } afterward .