public void setStopTimeout(int stopTimeoutInMillis) {
        this.stopTimeout = stopTimeoutInMillis;
    }
Time in milliseconds to wait when shutting down the processor, waiting on a latch inside
the onComplete method of the subscriber.  Default is 5000 milliseconds
@param stopTimeoutInMillis time to wait when shutting down the processor.
spring-xd-reactor/src/main/java/org/springframework/xd/reactor/AbstractReactorMessageHandler.java