code: public final <R, A> Mono<R> collect(Collector<? super T, A, ? extends R> collector) {
  		return Mono.onAssembly(new MonoStreamCollector<>(this, collector));
  	}
docs: Collect all elements emitted by this {@link Flux} into a container,
  by applying a Java 8 Stream API {@link Collector}
  The collected result will be emitted when this sequence completes.
  
  <p>
  <img class="marble" src="doc-files/marbles/collectWithCollector.svg" alt="">
  
  @param collector the {@link Collector}
  @param <A> The mutable accumulation type
  @param <R> the container type
  
  @return a {@link Mono} of the collected container on complete