code: @SafeVarargs
  	public static <I> Flux<I> mergeSequential(Publisher<? extends I>... sources) {
  		return mergeSequential(Queues.XS_BUFFER_SIZE, false, sources);
  	}
docs: Merge data from {@link Publisher} sequences provided in an array/vararg
  into an ordered merged sequence. Unlike concat, sources are subscribed to
  eagerly. Unlike merge, their emitted values are merged into the final sequence in subscription order.
  <p>
  <img class="marble" src="doc-files/marbles/mergeSequentialVarSources.svg" alt="">
  
  @param sources a number of {@link Publisher} sequences to merge
  @param <I> the merged type
  
  @return a merged {@link Flux}, subscribing early but keeping the original ordering