public static <F extends Future<Void>> Mono<Void> deferFuture(Supplier<F> deferredFuture) {
		return new DeferredFutureMono<>(deferredFuture);
	}
@Test
	void testDeferredFutureMonoImmediate() {
		ImmediateEventExecutor eventExecutor = ImmediateEventExecutor.INSTANCE;
		Supplier<Future<Void>> promiseSupplier = () -> eventExecutor.newFailedFuture(new ClosedChannelException());

		StepVerifier.create(FutureMono.deferFuture(promiseSupplier))
		            .expectError(AbortedException.class)
		            .verify(Duration.ofSeconds(30));
	}