reactor-core/src/main/java/reactor/core/publisher/ParallelFlux.java
public static <T> ParallelFlux<T> from(Publisher<? extends T> source,
			int parallelism) {
		return from(source,
				parallelism, Queues.SMALL_BUFFER_SIZE,
				Queues.small());
	}
public static <T> ParallelFlux<T> from(Publisher<? extends T> source,
			int parallelism) {
		return from(source,
				parallelism, Queues.SMALL_BUFFER_SIZE,
				Queues.small());
	}
Take a Publisher and prepare to consume it on {@code parallelism} number of 'rails',
possibly ordered and in a round-robin fashion.

@param <T> the value type
@param source the source Publisher
@param parallelism the number of parallel rails

@return the new {@link ParallelFlux} instance