public SimpleFileSink file(String dir, String fileName) {
		return SimpleFileSink.withDefaults(dir, fileName);
	}
Construct a new fileSink that will write the result to the dir and filename specified.

@param dir the directory the file will be written.
@param fileName the name of file to be written.
@return an instantiated file sink
spring-xd-integration-test/src/main/java/org/springframework/xd/integration/fixtures/Sinks.java