code: public final <U> Flux<T> timeout(Publisher<U> firstTimeout) {
  		return timeout(firstTimeout, t -> never());
  	}
docs: Signal a {@link TimeoutException} in case the first item from this {@link Flux} has
  not been emitted before the given {@link Publisher} emits.
  
  <p>
  <img class="marble" src="doc-files/marbles/timeoutPublisher.svg" alt="">
  
  @param firstTimeout the companion {@link Publisher} that will trigger a timeout if
  emitting before the first signal from this {@link Flux}
  
  @param <U> the type of the timeout Publisher
  
  @return a {@link Flux} that can time out if the first item does not come before
  a signal from a companion {@link Publisher}