reactor-core/src/main/java/reactor/core/publisher/Flux.java
@SafeVarargs
	public static <I> Flux<I> mergeSequential(Publisher<? extends I>... sources) {
		return mergeSequential(Queues.XS_BUFFER_SIZE, false, sources);
	}
@SafeVarargs
	public static <I> Flux<I> mergeSequential(Publisher<? extends I>... sources) {
		return mergeSequential(Queues.XS_BUFFER_SIZE, false, sources);
	}
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