reactor-core/src/main/java/reactor/core/publisher/ParallelFlux.java
public final <C> ParallelFlux<C> collect(Supplier<? extends C> collectionSupplier,
			BiConsumer<? super C, ? super T> collector) {
		return onAssembly(new ParallelCollect<>(this, collectionSupplier, collector));
	}
public final <C> ParallelFlux<C> collect(Supplier<? extends C> collectionSupplier,
			BiConsumer<? super C, ? super T> collector) {
		return onAssembly(new ParallelCollect<>(this, collectionSupplier, collector));
	}
Collect the elements in each rail into a collection supplied via a
collectionSupplier and collected into with a collector action, emitting the
collection at the end.

@param <C> the collection type
@param collectionSupplier the supplier of the collection in each rail
@param collector the collector, taking the per-rail collection and the current
item

@return the new {@link ParallelFlux} instance