public void copyHeadersIfAbsent(Map<String,Object> headersToCopy) {
		for (Entry<String, Object> headersToCopyEntry	 : headersToCopy.entrySet()) {
			if (!containsKey(headersToCopyEntry.getKey())) {
				put(headersToCopyEntry.getKey(), headersToCopyEntry.getValue());
			}
		}
	}
Set the payload
@param payload any non null object.
spring-xd-messagebus-spi/src/main/java/org/springframework/xd/dirt/integration/bus/MessageValues.java