code: public final Flux<T> cache(int history, Duration ttl) {
  		return cache(history, ttl, Schedulers.parallel());
  	}
docs: Turn this {@link Flux} into a hot source and cache last emitted signals for further
  {@link Subscriber}. Will retain up to the given history size and apply a per-item expiry
  timeout.
  <p>
  Completion and Error will also be replayed until {@code ttl} triggers in which case
  the next {@link Subscriber} will start over a new subscription.
  <p>
  <img class="marble" src="doc-files/marbles/cacheWithTtlAndMaxLimitForFlux.svg" alt="">
  
  @param history number of elements retained in cache
  @param ttl Time-to-live for each cached item and post termination.
  
  @return a replaying {@link Flux}