reactor-core/src/main/java/reactor/core/publisher/FluxProcessor.java
public static <IN, OUT> FluxProcessor<IN, OUT> wrap(final Subscriber<IN> upstream, final Publisher<OUT> downstream) {
		return new DelegateProcessor<>(downstream, upstream);
	}
public static <IN, OUT> FluxProcessor<IN, OUT> wrap(final Subscriber<IN> upstream, final Publisher<OUT> downstream) {
		return new DelegateProcessor<>(downstream, upstream);
	}
Transform a receiving {@link Subscriber} and a producing {@link Publisher} in a logical {@link FluxProcessor}.
The link between the passed upstream and returned downstream will not be created automatically, e.g. not
subscribed together. A {@link Processor} might choose to have orthogonal sequence input and output.

@param <IN> the receiving type
@param <OUT> the producing type

@param upstream the upstream subscriber
@param downstream the downstream publisher
@return a new blackboxed {@link FluxProcessor}