code: public final <U, V> Flux<T> timeout(Publisher<U> firstTimeout,
  			Function<? super T, ? extends Publisher<V>> nextTimeoutFactory) {
  		return timeout(firstTimeout, nextTimeoutFactory, "first signal from a Publisher");
  	}
docs: Signal a {@link TimeoutException} in case the first item from this {@link Flux} has
  not been emitted before the {@code firstTimeout} {@link Publisher} emits, and whenever
  each subsequent elements is not emitted before a {@link Publisher} generated from
  the latest element signals.
  
  <p>
  <img class="marble" src="doc-files/marbles/timeoutPublisherFunctionForFlux.svg" alt="">
  
  @param firstTimeout the timeout {@link Publisher} that must not emit before the first signal from this {@link Flux}
  @param nextTimeoutFactory the timeout {@link Publisher} factory for each next item
  
  @param <U> the type of the elements of the first timeout Publisher
  @param <V> the type of the elements of the subsequent timeout Publishers
  
  @return a {@link Flux} that can time out if each element does not come before
  a signal from a per-item companion {@link Publisher}