INT-4560: Fix Race in FileSystemPersistentAOFLF
JIRA: https://jira.spring.io/browse/INT-4560
Reproduced and tested with
```java
@SpringBootApplication
public class So53521593Application {
private static final Logger logger = LoggerFactory.getLogger(So53521593Application.class);
public static void main(String[] args) {
SpringApplication.run(So53521593Application.class, args);
}
@Bean
public IntegrationFlow flow() {
ExecutorService exec = Executors.newFixedThreadPool(10);
return IntegrationFlows.from(Files.inboundAdapter(new File("/tmp/foo")).filter(
new MyFilter(new SimpleMetadataStore(), "foo")),
e -> e.poller(Pollers.fixedDelay(5, TimeUnit.SECONDS)
.maxMessagesPerPoll(10)))
.channel(MessageChannels.executor(exec))
.<File>handle((p, h) -> {
try {
p.delete();
logger.info(p.toString());
Thread.sleep(10_000);
}
catch (InterruptedException e1) {
Thread.currentThread().interrupt();
}
return null;
})
.get();
}
}
class MyFilter extends FileSystemPersistentAcceptOnceFileListFilter {
public MyFilter(ConcurrentMetadataStore store, String prefix) {
super(store, prefix);
}
@Override
protected long modified(File file) {
long modified = super.modified(file);
System.out.println(modified);
return modified;
}
}
```
**cherry-pick to 5.0.x, 4.3.x**
39fef2c70a