code: public final ParallelFlux<T> filter(Predicate<? super T> predicate) {
  		Objects.requireNonNull(predicate, "predicate");
  		return onAssembly(new ParallelFilter<>(this, predicate));
  	}
docs: Filters the source values on each 'rail'.
  <p>
  Note that the same predicate may be called from multiple threads concurrently.
  
  @param predicate the function returning true to keep a value or false to drop a
  value
  
  @return the new {@link ParallelFlux} instance